Land Development Guidelines for the Protection of Aquatic Habitat files/fed land... · 2006. 8....

Land Development Guidelines

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Land Development Guidelinesfor the Protection of Aquatic Habitat

These guidelines were produced by the Habitat Management Division of the Department of Fisheries and

Oceans and the Integrated Management Branch of the Ministry of Environment, Lands and Parks.

The authors gratefully acknowledge all those people who contributed to the composition of these

guidelines.

Complied and edited by Barry Chilibeck, Department of Fisheries and Oceans,

and Geoff Chislett and Gary Norris, Ministry of Environment, Lands and Parks.

First Printing: May 1992

Second Printing: September 1993


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TABLE OF CONTENTS

TABLE OF CONTENTS..........................................................................................................3

LIST OF FIGURES.................................................................................................................5

SECTION 1INTRODUCTION....................................................................................................................9

SECTION 2LEAVE STRIPS......................................................................................................................15

SECTION 3EROSION AND SEDIMENT CONTROL AND SITE DEVELOPMENT PRACTICES................23

SECTION 4STORMWATER MANAGEMENT............................................................................................45

SECTION 5INSTREAM WORK.................................................................................................................63

SECTION 6FISH PASSAGE AND CULVERTS..........................................................................................69

SECTION 7IMPLEMENTING THE LAND DEVELOPMENT GUIDELINES.................................................81

SECTION 8LAND DEVELOPMENT EXAMPLE.........................................................................................89

APPENDIX IREGULATIONS......................................................................................................................109

APPENDIX IISALMONID HABITAT.............................................................................................................117

APPENDIX IIIOPERATING WINDOWS FOR FISHERIES SENSITIVE ZONES...........................................123

REFERENCES.......................................................................................................................127


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LIST OF FIGURES

Figure 2.1Riparian and Fisheries Sensitive Zones...................................................................................15

Figure 2.2Riparian Zone Benefits to Aquatic Habitat...............................................................................16

Figure 2.3Minimum Leave Strip for a Well-defined High Water Markin a Residential/Low Density Area...........................................................................................18

Figure 2.4Minimum Leave Strip Width for a Poorly-defined High Water Markin a Residential/Low Density Area...........................................................................................19

Figure 2.5Minimum Leave Strip for a Ravine or Steep-sloped Banksin a Residential/Low Density Area...........................................................................................20

Figure 2.6Plan View of Riparian Leave Strips..........................................................................................21

Figure 3.1Surface and Slope Erosion and Sediment Control Applications................................................27

Figure 3.2Typical Interceptor Ditch Construction and Application............................................................31

Figure 3.3Typical Silt Fence Construction and Applications.....................................................................33

Figure 3.4Sediment Control Pond Plan and Sections..............................................................................39

Figure 3.5Sediment Control Pond Riser Details and Baffle Layouts.........................................................40

Figure 3.6Single Lot Development Erosion and Sediment Control Features............................................44

Figure 4.1Dry Detention Pond Plan and Sections....................................................................................51

Figure 4.2Wet Detention Pond Plan and Sections...................................................................................53

Figure 4.3Detention Pond Control Structure Typical Details....................................................................54

Figure 4.4Infiltration System Design and Typical Application...................................................................58

Figure 4.5Coalescing Plate Oil-Water Separator.....................................................................................59

Figure 6.1Culvert Installation Limiting Fish Access..................................................................................72

Figure 6.2Culvert Providing Upstream Fish Passage...............................................................................73


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Figure 6.3Culvert Installation for a Small Creek with Provision for Fry Passage.......................................75

Figure 6.4Diagram and Photo of a Rock Outlet Pool and Tailwater Control Structure..............................78

Figure 6.5Diagram and Photo of Typical Culvert Baffle Layout and Installation........................................80

Figure 7.1Land Development Guidelines Screening and Application Chart..............................................84

Figure 8.1Predevelopment Map..............................................................................................................91

Figure 8.2Erosion and Sediment Control Map.........................................................................................94

Figure 8.3Developed Site Map................................................................................................................96

Figure 8.4Stream Information Summary (SIS) Report Data for Land Development Example...................97

Figure 8.5Land Development Example Site IDF Curves..........................................................................103

Figure 8.6Calculation of Predevelopment and Post-development Peak Flows for Land DevelopmentExample..................................................................................................................................106

Figure 8.7Calculation Spreadsheet and Simplified Hydrograph for Detention Volume Requirements.......107

Figure A2.1Anadromous Salmonid Life Cycle............................................................................................119

Figure A3.1Fisheries Sensitive Zone Areas of British Columbia.................................................................126


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LIST OF TABLES

Table 1.1 - Partial List of Agency Approvals for Land Development Projects............................12

Table 3.1 - Required Surface Area and Overflow Rates for Discrete Particle Settling...............35

Table 4.1 - Advantages and Disadvantages of Various Detention Technologies......................47

Table 6.1 - Fisheries and Design Considerations for Stream Crossing Structures....................70

Table 6.2 - Sustained, Prolonged and Burst Swimming Speeds For Various Fish....................75

Table 8.1 - Example Development Construction Schedule.......................................................91

Table 8.2 - Land Cover Factors used for Rational Formula......................................................98

Table 8.3 - Land Cover Factors used in Overland Flow Tc Calculation....................................99

Table 8.4 - Recurrence Intervals and Catchment Areas...........................................................100

Table 8.5 - Land Development Example IDF Data...................................................................101

Table A3.1 - Fisheries Sensitive Zone Species Timing Windows.............................................126


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SECTION 1INTRODUCTION

Purpose and ScopeThe purpose of these guidelines is to protect fish populations and their habitat from the damaging

effects of land development activities. The information contained in these guidelines pertains to

the preservation of Pacific salmon populations, a federally-managed resource (DFO), and

steelhead, trout, char and other freshwater species, which are managed by the provincial Ministry

of Environment, Lands and Parks (MOELP). These guidelines apply primarily to salmon, trout

and char, collectively termed salmonids, but are applicable to all fish species. Understandably,

the recommendations contained in these guidelines are generalized and, as such, are applicable

to a wide range of situations. Although the federal and provincial agencies work in close

association, it is important that both be contacted whenever a problem arises regarding fisheries

resources that cannot be resolved through reference to the land development guidelines. In

some instances and locations, it may be necessary for personnel of the federal and provincial

habitat management agencies to modify recommendations presented in these guidelines to

reflect site specific conditions and in order to protect salmonid habitat.

Fish Habitat, Land Development and Fisheries Sensitive ZonesDFO is responsible, under the Fisheries Act (R.S.C., 1985, c. F-14), to protect fish and fish

habitat in "waters frequented by fish" (Appendix I provides a brief regulatory synopsis for land

development purposes). This includes protection from any work in or near these waters. The

provincial government (MOELP) is responsible for management of steelhead, trout, char and

other non-salmonid freshwater species under the Fisheries Act. The definitions of fish and fish

habitat under the Fisheries Act are as follows:

• Fish all fish, shellfish, crustaceans and marine animals, and the eggs, spawn,

spat and juvenile stages of fish, shellfish, crustaceans and marine

animals.

• Fish Habitat the spawning grounds, nursery, rearing, food supply and migration areas

on which fish depend directly or indirectly in order to carry out their life

processes.

All developments in or adjacent to waters containing fish or fish habitat, whether marine or

freshwater, require the approval of DFO and MOELP. In order to better define the requirements

for protection of aquatic habitat, Fisheries Sensitive Zones (FSZ) were developed. They are

defined as the instream aquatic habitats, as well as the out-of-stream habitat features such as

side channels, wetlands and riparian areas. Land developments have the potential to seriously


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degrade and destroy fish habitat and impact fish populations. Accordingly, DFO and MOELP

carefully control work in and around the Fisheries Sensitive Zone.

Land Development Guideline ObjectivesThe primary goal of these guidelines is to ensure that the quantity and quality of fish habitat are

preserved and maintained at the productive level that existed prior to land development activities.

The Fisheries Act provides the legislative basis for DFO's Policy for the Management of Fish

Habitat (DFO 1986) and the principle of no net loss of the productive capacity (i.e. the maximum

natural capacity) of fish habitat. Each land development project, therefore, is subject to the

following guideline objectives.

• Provision and protection of leave strips adjacent to watercourses.

• Control of soil erosion and sediment in runoff water.

• Control of rates of water runoff to minimize impacts on watercourses.

• Control of instream work, construction and diversions on watercourses.

• Maintenance of fish passage in watercourses for all salmonid life stages.

• Prevention of the discharge of deleterious substances to watercourses.

The second goal of these guidelines is to encourage the provision of environmental

assessment/impact information to DFO and MOELP thereby improving the efficiency and

effectiveness of the regulatory referral and approval process. These guidelines are intended to

assist land developers to identify problems prior to development and present feasible solutions or

measures to prevent potential negative effects on fish and fish habitat. Their use will also avoid

potentially costly mitigation, restoration and compensation requirements. An overall awareness

of environmental concerns regarding land development, fish and fish habitat is essential if the

national goal of sustainable development is to be achieved.

Referral and Approval ProcessLand development projects are referred by individuals, companies and other agencies to both

DFO and MOELP. In most cases, the proponent of the project is responsible for providing the

required assessment information to the agencies involved. This information is summarized in an

impact assessment document, described later in the guidelines, that outlines the development

proposal and describes how the features of these guidelines will be incorporated. Generally, the

potential impacts on fish and fish habitat will be determined by DFO and MOELP staff based on

habitat function, productivity, uniqueness and sensitivity. The productive capacity is then rated

and used to evaluate the impact of the proposed development. If a potential impact exists,

alternate siting, mitigation or compensation options are examined to determine if no net loss can

be achieved. If no net loss can be achieved, the project will be approved under the Fisheries

Act. In some cases, additional information will be requested from the proponent to substantiate


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the impact assessment. If impacts are unacceptable and alternative siting, mitigation or

compensation are not possible, or the required information has not been provided, the project will

not be approved. Generally, early consultation with DFO and MOELP, and application of these

guidelines, will facilitate generation of a suitable land development plan. Proponents should

provide as much accurate information as possible so as to improve the efficiency of the process

for all parties concerned.

Federal Environmental Assessment and Review Process (EARP)The EARP process requires the lead federal agency (the agency with the primary decision-

making responsibility) on a project to carry out an initial environmental assessment screening. If

there are no impacts or the impacts can be mitigated with known technology, the project will be

allowed to proceed. If the screening indicates significant adverse impacts will result, the project

will be referred to the Minister of the Environment for public review by the Federal Environmental

Assessment Review Office (FEARO).

Regulation of Land Development - Other JurisdictionsWhile satisfying the requirements of the Fisheries Act is one step in the approval process, there

are a number of other possible requirements. Other federal, provincial, municipal or local acts or

by-laws may require applications, approvals and permits. These guidelines do not take

precedence over statutory and other requirements imposed by other agencies. Approval by DFO

in no way constitutes regional or local authority approval of the development of the project. On

the other hand, no approval given or implicit, by any regional or local authority, relieves the

proponent of responsibilities for the protection of the aquatic habitat as required by federal and

provincial statutes. Where fish habitat is damaged or lost, the powers of the Fisheries Act,

through the court system, may be used to order the proponent to restore or compensate for that

habitat and pay the associated expenses. Where other limits or conditions are specified by acts

or by-laws, the more stringent or limiting requirement shall take precedence. A list of some

federal, provincial and municipal statutes, approvals and permits is included in Table 1.1.


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Table 1.1 - Partial List of Agency Approvals for Land Development Projects

Agency Legislation Description

Federal:

Department of Fisheries

and Oceans

Fisheries Act Approval for activities that impact fish and

fish habitat including discharges of

deleterious substances. Requirements for

the provision of fishways, canals,

fishscreens or guards and the flow of water.

Transport Canada:

Canadian Coast Guard

Navigable Waters Protection Act Permit for activities in, around, under and

over navigable waters for commerce,

transportation or recreation.

Department of Indian

and Northern Affairs

Indian act Approval for activities on lands under

jurisdiction

Department of Energy, Mines

and Resources:

Explosives Branch

Explosives Act Use and transport of explosives.

Federal Environmental

Assessment Review Office

(FEARO)

Environmental Assessment and

Review Process Guidelines Order

Requirement for impact assessment,

environmental protection, EARP screening,

assessment and review. Administration of

public review panel.

Environment Canada:

Environment Protection

Canadian Wildlife Service

Inland Waters

Environmental Protection Act

Canadian Wildlife Act

Migratory Bird Conventions Act

International River Improvements

Act

Environment and human health, toxic

substances, water/air quality standards.

Permission for activities affecting wildlife and

wildlife habitat in wildlife areas.

Approval for activities affecting migratory

birds and their habitat.

Approval of work affecting water quality and

environment of rivers flowing outside

Canada.


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Table 1.1 - Partial List of Agency Approvals for Land Development Projects

Agency Legislation Description

Provincial:

Ministry of Environment, Lands

and Parks:

Regional Operations

Water Management Branch

Environmental Protection Division

Crown Lands Branch

Environmental Assessment

Branch

Fisheries Act

Water Act

Waste Management Act

Land Act

Environment Management Act

Approval for activities that impact fish and

fish habitat.

Approval for short term use, storage and

diversion of water. Approval of alterations

and work in and about a stream (Section 7).

Permit the discharge or emission of effluent,

waste or contaminants into air, land or water.

Restrictions regarding solid and toxic

wastes.

Regulation of the sale, lease and license of

occupation, rights-of-way, special use

permits, easements, map reserves and

permission to construct on crown lands.

Requirements for impact assessment and

environmental protection as ordered.

Ministry of Agriculture, Fisheries

and Food:

Agricultural Land Commission

Soil Conservation Act

Agricultural Land Commission Act

Permit for the removal of soil from an ALR.

Regulations to prevent and control soil

erosion.

Approval to use land in the ALR for other

than farm use.

Ministry of Health:

Provincial Health Officer

Health Act Approval of construction camps.

Regulations for potable water supply,

sewage disposal, sanitation and food supply

operations.

Ministry of Attorney General:

Fire Commissioner

Fire Services Act Approval for more than 22.5 liters of fuel

storage onsite and onsite fuel dispensing.

Ministry of Municipal Affairs,

Recreation and Housing:

Archaeology Branch

Heritage Conservation Act Approval to excavate or alter sites of

archaeological or historical significance.

Regional/Municipal:

Regional/Municipal Governments Municipal Act

Regional and Municipal By-laws

Permits for construction. Approval of zoning

or re-zoning. Regulation of set backs,

development densities (FSR), local land use

and building codes. Permits for clearing and

burning.


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Review and Updating of the Land Development GuidelinesThese guidelines will be reviewed and updated every two years to account for changes in

technologies, standards or requirements regarding land development and its associated impacts

on the aquatic environment. Comments and input into these guidelines are welcomed and

should be forwarded to:

Department of Fisheries and Oceans Canada

Habitat Management Division

Station 327 - 555 W. Hastings Street

Vancouver, BC V6B 5G3

phone: 666-6566

fax: 666-7907.


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SECTION 2LEAVE STRIPS

ObjectiveThe primary objective of leave strips is to protect the riparian zone, which is critical to the

maintenance of a healthy aquatic environment. Riparian zones, located next to streams, rivers,

lakes and wetlands, have direct influence on aquatic habitat values. They can broadly be

described as the area of the streambank, including any side channels and associated banks, and

the area of influence, which contains upland areas not normally inundated during high water

conditions. Riparian zones and the instream aquatic habitat are both part of the Fisheries

Sensitive Zone (FSZ). Leave strips are the areas of land and vegetation adjacent to

watercourses that are to remain in an undisturbed state, throughout and after the development

process. The extent of the leave strip will be determined by the presence and proximity of a

watercourse on or adjacent to the development site, and by the nature of the watercourse and

surrounding land use. Leave strips should be provided on all watercourses that flow into

or contain fish or fish habitat. This may include wetlands, ponds, swampy areas or

other intermittently wetted areas, small streams, side channels and ditches which may

not flow throughout the entire year (ephemeral). The leave strip also helps to protect

private property from flooding and potential loss of land due to stream erosion and instability.

Figure 2.1 Riparian and Fisheries Sensitive Zones


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Impact of Riparian Zones on Aquatic Fish HabitatThe riparian zone has characteristics that protect and nurture quality aquatic fish habitat.

Disturbance or destruction of the riparian zone can have serious impacts to both the short and

long-term viability and productivity of fish and fish habitat.

Figure 2.2 Riparian Zone Benefits to Aquatic Habitat

Food Source

The largest supply of food items and material supporting the aquatic food chain originates from

outside the stream's waters. Riparian zones provide food directly by providing habitat for

terrestrial insects that fall into the water becoming food items for fish. The organic matter, leaves

and needles provide a food source for many aquatic insects which in turn become food items for

fish.

Large Organic Debris (LOD) Source

The large mature deciduous and coniferous trees along a streambank provide a future source of

large organic debris in the aquatic environment and should be preserved. Fallen dead trees and

snags, eroded root structures and logs are the large organic debris that provides stream bed

stability, cover and habitat for young fish. LOD should not be removed from the stream FSZ.


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Water Temperature Regulation

The density and height of the streamside vegetation influence the amount of light reaching the

water surface, hence water temperatures and dissolved oxygen saturation levels of streams. A

developed canopy provides a stable shading influence which helps regulate water temperature

ranges and rates of fluctuation. This ultimately reduces stress on fish populations and improves

habitat quality.

Stream Buffer Zone

Streamside vegetation and ground cover intercept runoff and act as an effective filter for

sediment and pollutants that would normally be deposited into the water column and would

impact fish and fish habitat.

Stream Cover

Streamside vegetation plays an important role by providing cover and shelter which reduces

stress and losses from predation for both juvenile and adult salmonids.

Streambank Stability

The living network of roots and vegetation provide "living rip rap", limiting bank erosion and

stream degradation. Channel stability enhances aquatic habitat values in productive stream

reaches.

Permanent Protection of Leave StripsThe leave strip should be permanently protected under one of the following methods: dedication

as park, by return of the land to the Crown in the name of the local government, re-zoned as a

protected area or reserve status, or secured with restrictive covenants. The development of trails

for public access and use may be considered, however they should not be designed or

constructed so that they adversely affect the stream's aquatic habitat and should be included in

the overall development plans for DFO/MOELP review.

Leave Strip BoundariesOnce the extent of the leave strip has been determined, the boundary must be defined by legal

survey and depicted on the appropriate development project drawings as "Leave Strip". Leave

strip boundaries should be clearly defined in the field (e.g. by the installation of snow type

fencing) prior to the commencement of any site work. The fencing should be securely fastened

on posts to prevent movement and have signs notifying the leave strip boundary. Such boundary

definition should remain in place and be maintained in good order until completion of construction

of buildings on the site. It can be removed as part of final inspection on completion of the site

work. To prevent incursions into the leave strip after construction or to protect sensitive areas,

permanent fencing should be installed.


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Leave Strip WidthsMinimum leave strip widths for riparian zone protection can be established with these guidelines.

The stream high water mark must first be determined, usually the water level reached during the

mean annual flood event or top of the stream bank, and the widths specified are then measured

from that high water mark. They are measured perpendicular to and away from the stream bank,

for the distance specified, on both sides of the stream. These are suggested minimum

widths and may be altered by DFO/MOELP staff to suit onsite conditions . DFO or

MOELP should be contacted if there is any difficulty in determining the existing high

water mark, or required leave strip width for a certain watercourse or development . In

many cases, the leave strip may have to be widened to protect critical fish habitat within the FSZ.

Many regional and municipal authorities have specific zoning and set-back requirements for flood

protection, parks, community planning, etc. They will take precedence if they exceed the

minimum requirements of these guidelines.

Watercourse with well defined high water mark in a Residential/Low Density Area

The minimum leave strip width on each side of the watercourse should be 15 meters from the

high water mark.

Figure 2.3 Minimum Leave Strip for a Well-defined High Water Markin a Residential/Low Density Area


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Watercourse with poorly-defined high water mark in a Residential/Low Density Area

Careful consideration must be given to establishing the existing high water mark in wide flood

plain or multi-channel areas, and features such as floating vegetation mats, undercut banks and

seasonally dry areas, must be taken into account. These areas usually have high salmonid

habitat values and require protection because they are difficult to restore or compensate for if

damaged or destroyed. The minimum leave strip width on each side of the watercourse should

be 15 meters from the high water mark.

Figure 2.4 Minimum Leave Strip Width for a Poorly-defined High Water Markin a Residential/Low Density Area

Watercourse with steeply sloped topography in a Residential/Low Density Area

Steep slopes adjacent to watercourses have the potential for major adverse effects on aquatic

habitat. Major problems are generally due to erosion, gully formation, loss of riparian vegetation

and bank instability associated with surface runoff down steep slopes. Additional stream channel

instability can cause channel and bank erosion resulting in large-scale mass wasting and

sediment inputs to the aquatic habitat. Leave strips at the top of slopes provide an effective

buffer for the entire ravine area and protect the sensitive crest areas. Accordingly, leave strip

widths should maintained at the top of the ravine or steep sloped areas. If the distance from the

high water mark to the toe of the slope is less than 15 meters, then the leave strip should be

located at the first significant and regular break in slope which is a minimum of 15 meters wide.


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Figure 2.5 Minimum Leave Strip for a Ravine or Steep-sloped Banksin a Residential/Low Density Area

Watercourse with well defined high water mark in a Commercial/High Density Area

Because of higher utilization of land and development of impervious areas within commercial,

industrial and multi-family/multi-dwelling developments, the potential for increased impacts on

watercourses can be great. Accordingly, protective leave strips should be widened to provide

additional protection. The minimum leave strip width on each side of the watercourse should be

30 meters from the high water mark

Watercourse with poorly-defined high water mark in a Commercial/High Density Area

Similar to a residential/low density area, but with an increased minimum width to allow for higher

land utilization. Where the watercourse is ill-defined, the minimum leave strip width on each side

of the watercourse should be 30 meters from the high water mark.

Watercourse with steeply sloped topography in a Commercial/High Density Area

Similar to a residential/low density area, but with increased minimum width to allow for higher

land utilization. If the distance from the high water mark to the toe of the slope is less than 30

meters, then the leave strip should be located at the first significant and regular break in slope

which is a minimum of 30 meters wide.


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Figure 2.6 Plan View of Riparian Leave Strips


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Guidelines for Construction Practices within the Fisheries Sensitve ZoneThe following provisions are steps intended to protect leave strips and maintain a healthy

functional riparian zone. For additional information regarding work within the FSZ, see Instream

Work and Appendix III.

Planning and Minimizing Impacted Area

• Streambank characteristics and vegetation should be taken into account when planning

development activities in and around rivers and streams.

• During development of the land, there should be no unauthorized work or disturbance

into the FSZ.

• Where encroachment into a leave strip is required, specific plans must be prepared and

approved by DFO/MOELP in advance.

• Requests for permission to encroach will only be considered for major vehicle or

footbridge crossings, utility crossings, and stormwater discharge outfalls.

• The plans for such encroachments should include details including the extent of work

areas; plans for the control of water discharged from the work area; the timing of work;

and the details for restoration after construction.

• Carefully select access points to streambank through the riparian zone, minimize the size

and duration of disturbance, and preserve streamside vegetation and undergrowth

wherever possible.

• Limit machinery and equipment access and direct disturbance to streambank areas.

Stabilizing Impacted Area

• Physical stabilization of eroding or eroded banks may be required to promote bank

stability and regeneration of riparian vegetation.

• Design and construction of stabilization works should prevent their subsequent erosion.

• Remove disturbed, unstable debris from the riparian zone to prevent it from being swept

away during high water.

• Retain stable large organic debris (LOD) which does not impede flows and fish migration,

or promote bank erosion.

Revegetating Impacted Area

• Revegetate disturbed areas immediately following completion of work in riparian zones.

• Establish ground cover to prevent surface erosion and deeper rooted plants and shrubs

to prevent streambank erosion.

• Cedar, vine maple, alder, cottonwood, willow, salmonberry and red osier dogwood are

common native plants used to augment brush and large plant formation.

• Large tree species will provide long-term sources of LOD.


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SECTION 3EROSION AND SEDIMENT CONTROLAND SITE DEVELOPMENT PRACTICES

ObjectiveLand development activities, such as clearing land, grading slopes, road building, and excavation

and stockpiling of materials, can lead to the erosion of soils into nearby watercourses. These

watercourses may contain fish and fish habitat, or flow into other streams that do. Increased

surface runoff as a result of the development, due to lack of vegetation, infiltration and ponding,

and the loose condition of disturbed soils leads to increased downslope transport of soils by the

runoff. Even after the replacement and compaction of slopes and surfaces, soil erosion, gully

and channel formation can occur. Sediments are composed of undissolved organic and

inorganic materials ranging in size from microscopic particles to boulders, transported by flowing

water. The finer material is carried suspended in the volume of water and is known as

suspended sediment or suspended load. Larger material, generally consisting of coarse sand,

gravels, and boulders, is carried along the channel bottom by the flow of water and is known as

bed load. Understandably, on and offsite runoff management is a key factor in erosion and

sediment control. Additionally, by preparing and covering disturbed soils, revegetating slopes

and lining runoff channels, the amount of soil available to be eroded can be reduced. The

objective of these erosion and sediment control guidelines is to minimize sediment inputs into fish

habitat by reducing the potential for erosion, by stabilizing disturbed soils and intercepting

sediment-laden runoff. Erosion and sediment control is extremely important because sediment

can have severe negative impacts on all life stages of fish and their habitat. The following are

examples of key fish and fish habitat impacts.

• Suspended sediment can settle on spawning areas, infill the intragravel voids and

smother the eggs and alevins in the gravel.

• Bed load and settled sediments can infill pools and riffles, reducing the availability and

quality of rearing habitat for fish.

• Suspended sediment can clog and abrade fish gills, causing suffocation or injury to fish.

• Suspended sediments can reduce water clarity and visibility in the stream, impairing the

ability of juvenile fish to find food items.

• Settled sediments can smother and displace aquatic organisms (benthic invertebrates),

reducing the amount of food items available to fish.

• Increased levels of sediment can displace fish out of prime habitat into less suitable

areas.


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Erosion and Sediment Control MethodsThe key factors in erosion and sediment control are to intercept and manage off and onsite

runoff. This limits the potential for soils to be eroded and form sediments in surface runoff.

Runoff and surface erosion control is more effective and less expensive than sediment control

with sediment control ponds only. Sediment control ponds have a limited capacity to remove

sediments and are a last line of defense against sediment entering watercourses. Sound and

sensitive development and construction practices are far more effective in complying with the

objectives of these guidelines. Described below are the general principles of erosion and

sediment control (ESC) and their application to land development activities (from Goldman,

1986).

Plan the development to the existing terrain and site conditions.

• Design and plan the development of roads, utilities and building sites with as little soil

excavation and disturbance as possible.

• Design and plan development for the particular soil conditions and topography of the site.

• Confine construction to least critical areas and minimize impervious areas.

• Consider non-development of land in areas with extremely sensitive fish habitat values.

Schedule development to minimize risk of potential erosion.

• Where possible, plan construction activities during dry months of the year to avoid

potential rain events and delays.

• Stage development to allow "green-up" or re-establishment of vegetation and minimize

erosive areas.

• Halt construction during periods of heavy precipitation and runoff to minimize soil

disturbance.

• Restrict vehicular and equipment access or provide working surfaces/pads.

Retain existing vegetation where possible.

• Minimize clearing rights-of-way and stripping of building sites.

• Avoid clearing and grubbing areas with sensitive soils.

• Consider aesthetics and retention of vegetation, including undergrowth.

• Physically mark clearing boundaries on the construction site.

Re-vegetate/protect denuded areas and bare soils.

• Seed or re-vegetate cut and fill slopes, and disturbed natural slopes.

• Cover temporary fills or stockpiles with polyethylene sheeting or tarps.

• Use mulches and other organic stabilizers to minimize erosion until vegetation is

established on sensitive soils.

• Plan seeding and planting to allow establishment before end of growing season

Divert runoff away from denuded areas.


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• Minimize flow over bare areas by diverting overland flows away from development areas.

• Isolate cleared areas and building sites with swales to re-direct runoff.

• Avoid steep slopes below rills and gullies.

• Retain natural drainage patterns wherever possible.

Minimize the length and steepness of slopes where possible.

• Erosion and soil loss is greater the longer and steeper the slope. Minimize both length

and steepness of all slopes at engineering/planning stage.

Minimize runoff velocities and erosive energy.

• Maximize the length of flow paths for precipitation runoff to minimize energy of flow.

• Construct interceptor ditches and channels with low gradients to minimize secondary

erosion and transport.

• Line unavoidably steep interceptor or conveyance ditches with filter fabric, rock or

polyethylene lining to prevent channel erosion.

Design development for increased runoff.

• Design and engineer ditches and channels for post development flows.

• Construct stable, non-erodible ditches, inlet and outlet structures.

Retain eroded sediments onsite with erosion and sediment control structures.

• Utilize sediment traps and silt fences.

• Provide bed load clean-outs at culverts and ditches.

• Construct and operate sediment control ponds.

Plan, inspect, and maintain erosion and sediment control structures.

• Develop and follow a maintenance and inspection schedule as part of the development

plan.

• Stockpile the required erosion/sediment control materials: filter cloth, rock, seed, drain

rock, culverts, staking, matting, polyethylene, used tires, etc.


26

Slope ProtectionThe following techniques should be employed to prevent the initiation of surface soil erosion and

movement of sediments from slopes. The surface preparation applied to slopes can be

determined by the type of material and grade of the slope. The measures used for erosion and

sediment control on slopes are as follows.

• Application of surface protection.

• Application of silt fences.

• Design and installation of interceptor ditches.

• Application of other land development erosion control features or approved erosion

control measures.

Conditions of implementation of these erosion and sediment control measures for slopes should

be as follows.

• In dry conditions, all cut/fill and cleared natural slopes and surfaces should have erosion

controls implemented within 14 days.

• In wet conditions, erosion control should be implemented immediately on completion of

the grading operations of the worked area.

• Slopes exceeding 3.0 meters in height and steeper than 2H:1V should be reviewed by a

Professional Engineer to assess slope stability, erosion, and drainage control

requirements.

The photographs in Figure 3.1 illustrate some prominent features of both slope and surface

erosion control structures.

Temporary Slopes

Protection for a duration up to 6 months. Temporary slope preparations are determined by

subgrade type (below) and slope/erodibility.

• Bed Rock/Hard Glacial Till Subgrade:

Slopes may be left exposed.

• Silt, Sand, Mixed Sand/Gravel Subgrade:

Temporary surface protection.

• Organic or Top Soil Subgrade:

Temporary surface protection.

• Coarse Gravel/Cobble Subgrade:

Slopes may be left exposed. No surface protection unless erosion develops.


27

Figure 3.1 Surface and Slope Erosion and Sediment Control Applications


28

Long Term or Permanent Slopes

Protection for a duration exceeding 6 months. Permanent slope preparations are determined by

subgrade type (below) and slope/erodibility.


Slopes may be left exposed.

• All Other Subgrade Types:

Permanent surface protection.

Soil Excavation Stockpiles

All soil which is stockpiled for more than 7 days and less than 2 months should be covered with

polyethylene or totally contained by a silt fence as a temporary measure to prevent erosion.

Longer term stockpiles should be shaped to have side slopes no steeper than 1.5H:1V and

remain covered with polyethylene, or have temporary surface protection applied.

Graded Areas

Temporary graded areas, such as housing lots, should be protected from erosion through the use

of straw mulch and/or polyethylene tarps in non-traffic areas and a gravel cap in zones of

construction traffic. Final graded or landscaped areas should have the appropriate permanent

surface protection or landscaping in place as soon as possible.

Surface ProtectionThe purpose of these techniques is to absorb raindrop impact, reduce runoff velocity, improve

infiltration, bind soil particles with roots, and protect the soil from the wind. The rapid

establishment of a vegetation cover is generally recognized as the most cost effective form of

surface erosion control. Protection of the soil surface with mulches or other materials will provide

immediate erosion control until vegetation is established. When time is limited or vegetation

establishment is not a goal, or weather conditions are unsuitable, the use of polyethylene

sheeting or tarps is recommended.

Temporary Surface Protection

Surfaces and slopes less than 2H:1V use Seeding with Straw Mulch:

• Soil surfaces to be treated should be rough. Scarify to a maximum depth of 2.5 cm if

necessary. Broadcast 100% fall rye seed at a rate of 50 kg/ha. Include 19-23-14

fertilizer at a minimum rate of 200 kg/ha.

• Cover the seeded area with at least 5 cm of straw, preferably applied with a blower. The

straw should be held in place with a hydroseeder application of wood fiber mulch at 500

kg/ha and a tackifier at 40 kg/ha, or with netting.


29

Surfaces and Slopes up to 1H:1V use Seeding and Hydromulching:




• Apply wood fiber mulch (designed for hydroseeding) at a rate of 2500 kg/ha together with

tackifier at a rate of 60 kg/ha (or at the manufacture's recommended rate) with a

hydroseeder to form a continuous blotter-like cover.

Highly Erodible Surfaces and Slopes use Seeding and Erosion Control Revegetation

Matting (ECRM):




• Roll the ECRM, a biodegradable pre-seeded erosion control mat, upon the soil surface

and anchor it at the top. It needs to be adequately stapled to ensure it remains in place

and in direct contact with the soil.

Highly Erodible Surfaces and Slopes use Polyethylene Cover

When immediate protection is needed or other protective techniques are not feasible,

polyethylene sheeting or tarps can be used. It should be well anchored to resist wind (old tires

are ideal) and prevent major leakage. Breaks in the cover should be repaired immediately.

Polyethylene sheeting is not recommended for use on sites to be left idle for more than 2 months,

unless weather conditions preclude the establishment of vegetation.

Permanent Surface Protection

Protection within 14 days for a duration exceeding 6 months. Options are identical to those

described for temporary surface protection except for the following changes:

• The broadcast seed application should consist of fall rye at a rate of 20 kg/ha, plus the

following mix (all percent by weight) at a rate of 60 kg/ha.

25% creeping red fescue 15% hard fescue

5% redtop 15% orchard grass

20% perennial ryegrass 10% alsike clover

10% white clover

• The fertilizer should consist of standard commercial materials, with at least 60% of the

nitrogen in the form of slow release urea. The rate of application should be based on

laboratory soil analysis, with a minimum of 400 kg/ha of 19-20-12.

• All permanent surfaces and areas that are in final form and are to be vegetated as per

the landscape plan, should be done as soon as practically possible (delays greater than

14 days, temporary slope and surface protection should be applied).


30

Interceptor DitchesInterceptor ditches are structures designed to intercept and carry clean surface runoff away from

erodible areas and slopes, reducing the potential surface erosion and limiting the amount of

runoff requiring treatment. Alternatively, they can collect sediment contaminated runoff from

slopes and carry it, without further erosion, to treatment areas or sediment ponds. Figure 3.2

shows typical installations of interceptor ditch structures as well as ditch lining types.

Design of Interceptor-Conveyance Ditches

• The location and access to interceptor ditches should be determined following analysis of

the topography, the existing or planned drainage pattern and subgrade conditions. They

should be laid out, following contours if possible, and constructed during initial clearing.

• Interceptor ditches should be located along the uphill boundaries of development sites,

the uphill sides of major cut and fill slopes, to intercept and convey overland runoff.

• Interceptor-conveyance ditches should be designed to take a 2 year (1:2) storm runoff

flow with 0.3 meters freeboard. Sideslopes should be no steeper than 1H:1V.

Construction of Interceptor Ditches

The construction and protection of the ditch should be based on the expected design flows,

subgrade soil conditions, gradient and design life.


Ditches can remain unlined.

• Silt, Sand, Mixed Sand/Gravel, or Organic Subgrade:

Ditches should be lined with 0.6 mm polyethylene if it is overlapped 0.5 meters, bedded

on non-angular material, and the top edges are anchored in small (0.30 meter deep)

trenches along the top of the ditch. The subgrade should be free of any angular material.

• Coarse Gravel/Cobble Subgrade:

Shallow gradient ditches may remain unlined. Steep gradient ditches should be

armoured or lined with polyethylene as above.

• Steep Gradient and/or Large Volume Ditches:

Steep gradient and/or ditches carrying a large volume of water will require full rock

armouring to design water levels to prevent scour and bank erosion.

• Interceptor ditches may require energy dissipators at changes in grade and elevation, as

well as armouring at changes in direction. Energy dissipators may be weirs built of

broken rock, gabions, concrete or timber. The location and design of energy dissipators

should be done by a Professional Engineer.


31

Figure 3.2 Typical Interceptor Ditch Construction and Application


32

• Excavated bed load traps or pools formed by gravel berms can be constructed to collect

eroded material. They should be located downstream of points of sudden reduction in

gradient. They should be cleaned out after heavy rainfall or during periods of sustained

precipitation.

• Sideslopes should be seeded to reduce erosion and subsequent maintenance, and also

to improve appearance, especially for permanent works. Temporary ditches should be

filled and the area reclaimed when they are no longer required.

• A regular, permanent maintenance program is necessary to keep ditches in good working

order. Silt has to be removed from silt traps, weirs may have to be adjusted or repaired,

additional rip-rapping may be necessary. All ditches and structures should be inspected

after heavy rainfall or during periods of sustained precipitation.

Silt FencesSilt fences and related structures provide an effective filter for sediment-laden runoff from eroded

slopes and surfaces. The fine openings do not allow the passage of sediment coarser than about

0.02 mm. Silt fences are effective boundary control devices, trapping the sediment close to the

erosion source and preventing mobilization into runoff, but have a limited sediment retention

capacity. Figure 3.3 illustrates some typical applications using silt fences for erosion control, and

design parameters.

• Silt or filter fences should be installed on the lower perimeter of slopes (lower 1/3 to 1/2

of site) and areas where the erodibility is high and/or it is desirable to contain waterborne

movement of eroded soils. Such areas include the bottom of cut or fill slopes, material

stockpiles and disturbed natural areas.

• Filter fabric or geotextile may be a pervious sheet of slit film woven polypropylene, nylon,

polyester, or ethylene yarn, having the following properties.

• Minimum Filtering Efficiency 90%.

• Minimum Flow Rate 0.012 m3/m2/minute.

• Minimum grab tensile strength 700 N.

• Minimum equivalent opening size 0.15 mm (median 0.21 mm).

• If standard strength filter fabric is used it must be backed by a wire fence supported on

posts not over 2.0 meters apart. Extra strength filter fabric may be used without wire

fence backing if posts are not over 1.0 meters apart. Fabric joints should be lapped at

least 0.15 meters and stapled. The bottom edge should be anchored in a 0.30 meter

deep trench, or some equivalent manner, to prevent flow under the fence.

• If the filter fabric decomposes or becomes ineffective, it must be replaced and the fence

repaired.


33

Figure 3.3 Typical Silt Fence Construction and Applications


34

Other Erosion Control MeasuresThe following sediment and erosion control structures are used to varying degrees to mitigate

onsite erosion and control runoff.

Sediment Traps

Sediment traps should be installed at the lowest point on each lot prior to excavation and

construction on the site. Swales or ditching should convey surface runoff to these traps prior to

pumping or discharge from the site. Sediment traps operate like small sediment control ponds by

controlling the discharge of sediment offsite.

Swales

Swales are effective at re-directing surface runoff away from erodible sites and reducing the

amount of sediment laden runoff generated onsite. They should be constructed of clean, non-

erodible granular material in 0.3 meters high ridge with a low gradient to prevent scouring and

further sedimentation.

Gravel Berms, Small Silt Fences, Check Dams and Bale Structures

These should be installed in overland flow paths, swales and other possible locations of

concentrated flow to arrest migration of erodible soils. Their number and spacing will depend on

the nature of the construction operations. They are effective at controlling sediment close to its

source.

Culverts

Groundwater seepage and other small flows can be contained and flumed away from sensitive

slopes and cut banks to prevent erosion of toe areas and maintain slope stability. They are also

effective for conveying flows down steep slopes where it would be impossible to convey through

an open channel.

New Drainage Systems

Storm sewer and drainage systems should have their inlets blocked, or should have sediment

traps installed at inlets until all work is complete. During curb construction, roadside drainage

should be temporarily controlled in swales and directed into the storm sewer system at suitable

locations provided with sediment traps. Systems can be utilized for conveying flows to sediment

control ponds.


35

Sediment Control PondsDesign of Sediment Control Ponds

Sediment control ponds are the last line of defense before runoff is discharged from the

development site. There is a practical limitation on the minimum size of particles that can be

settled because of particle size, settling characteristics, residence time and land area available

for sediment ponds. This minimum size has been set at 0.02 millimeters (mm) which equals a

settling velocity (vs) of 0.02 cm/s @ 0°C. Even at design flows, many particles smaller than 0.02

mm will pass through the sediment control pond and can be deleterious to fish and fish habitat.

This emphasizes the importance of minimizing the amount of site soils eroded and allowed to

enter the sediment control ponds. The table below illustrates the increasing pond area (m2)

required per unit flow (m3) to provide discrete particle settling using the following equation and

assuming a specific gravity of solids = 2.65:

AQ

vs

= 1 2. Erosion and Sediment Control, USEPA, 1976.

Table 3.1 - Required Surface Area and Overflow Rates for Discrete Particle Settling(m2 pond area per m3 of flow)

particleclassification

particlediameter(microns)

WaterTemperatur

e

0°C 5°C 10°C 15°C 20°C

coarse sand 1000 3 3 3 3 3

medium sand 500 8 7 6 5 5

fine sand 250 40 33 28 23 19

coarse silt 62 621 528 455 396 464

medium silt 31 2486 2111 1819 1583 1389

fine silt 16 9332 7924 6829 5943 5213

very fine silt 8 37327 31697 27318 23773 20853

coarse clay 4 149310 126788 109271 95091 83413

medium clay 2 597239 507153 437085 380364 333653

fine clays 1 2388956 2028611 1748342 1521458 1334612

The proper design and operation of settling facilities in no way removes the

responsibility of the proponent from achieving the site runoff water quality objectives .

Where the use of gravity settling will not provide the required effluent quality, or where lack of

space does not permit provision of such facilities, the proponent may wish to consider the use of

mechanical settling devices or chemical agents. The design requirements of such facilities are


36

beyond the scope of these guidelines and would require detailed plans prepared by a

Professional Engineer. Such an installation would also require approval from MOELP -

Environmental Protection Division for operation, maintenance, discharge and disposal of the

residue.

Site Runoff Water Quality Requirements

Runoff water from the development site should contain less than 25 mg/liter of suspended solids

(or non-filterable residue, NFR) above the back-ground suspended solids levels of the receiving

waters during normal dry weather operation and less than 75 mg/liter of suspended solids above

background levels during design storm events. However, where spawning areas are situated in

the receiving waters, the storm runoff water discharged should not, at any time, increase

suspended solids levels above background suspended solids levels in the receiving waters.

Background suspended solids levels are the natural instream suspended solids or NFR levels

measured upstream of the point of discharge in the watercourse. If there is any question

regarding the normal dry weather or design storm background level, DFO or MOELP

staff should be contacted .

Location and Number of Sediment Control Ponds

• Sediment control ponds should be located at the lowest practical point in the catchment

area.

• The location, number, and size of ponds will reflect the area being developed at any one

time, but a minimum of two (2) should be constructed.

Design Parameters for Sediment Control Ponds

• Design particle size 0.02 mm.

• Design pond area developed site 5 year (1:5) storm to calculate

design area based on runoff flow and design

particle or minimum of 1% of the total erodible

area.

• Design horizontal velocity horizontal velocity which will not cause

suspension or erosion of deposited material.

• Design hydraulic retention time minimum of 40 minutes.

• Design drawdown time 48 hours with no incoming flow or loss of

accumulated solids.

• Overflow spill capacity developed site 1:10 year (1:10) storm event.

• Emergency spillway capacity developed site 1:100 year (1:100) storm event.


37

Dimensions and Capacities of Sediment Control Ponds

• Minimum effective flow path 5 times the effective pond width.

• Minimum freeboard 0.6 meters.

• Minimum free settling depth 0.5 meters above the top-of-sediment elevation.

• Minimum sediment storage depth 0.5 meters.

• Maximum interior sideslopes 2H:1V.

• Maximum exterior sideslopes 3H:1V.

Inlet and Outlet Structures of Sediment Control Ponds

• The inlet should distribute incoming flow across the width of the pond.

• Bypass piping or multiple ponds should be installed to allow pond servicing.

• A pre-treatment sump to remove coarse sediments is required.

• Only clarified surface water should be allowed to leave the pond.

• The dewatering drawdown holes should be protected with a granular filter to prevent

formation of high velocity currents which could resuspend settled sediment.

• Discharge and conveyance of discharged pond flows should not cause erosion of natural

drainage systems. Plastic culvert piping should replace ditching for temporary pond

applications to limit disturbance in the FSZ.

Operation and Maintenance of Sediment Control Ponds

• Settled sediment should be removed after each storm event or when the sediment

capacity has exceeded 33% of design sediment storage volume.

• Periodic inspection and removal of accumulated sediments and the required inspection

and maintenance interval should be noted on the design drawings.

• Accumulated sediment removed during pond maintenance must be disposed of in a

manner which will prevent its re-entry into the site drainage system, or into any

watercourse.

• The tops of slopes or berms around sediment control ponds should be wide enough to

provide a safe and stable work area where required for the operation of maintenance

equipment and personnel and should be covered with crushed stone and/or turf stone to

prevent damage to the structure, and loosening of soil which could wash into the pond.

• Multiple ponds or a single large superpond may be designed for a large development, but

a minimum of two should be constructed for pond maintenance requirements.

• Sediment control ponds should be constructed during initial site development and

maintained until all building construction and site grading work is completed. Sediment

ponds may be retrofitted for use as stormwater detention ponds.


38

Stability and Public Safety of Sediment Control Ponds

• The stability of sideslopes for all earthen ponds should be confirmed by a Professional

Engineer. All interior sideslopes in areas subject to water level fluctuations should be

stable against pore water pressure during rapid drawdown. Exterior sideslopes should

be structurally stable under all loads and hydraulic conditions.

• Suitable fencing and signage should extend around the perimeter of all ponds.

• Discharge risers greater than 450 mm diameter should have a trash rack to exclude large

objects.

• See Figures 3.4 and 3.5 for typical sediment control pond design and details.


39

Figure 3.4 Sediment Control Pond Plan and Sections


40

Figure 3.5 Sediment Control Pond Riser Details and Baffle Layouts


41

Guidelines for Control of Deleterious Substances on the Development SiteCommon deleterious substances: sediments, raw and uncured concrete, mortar, glues, paints,

lubricants, organic and inorganic contaminants, fuels and oils, can have detrimental or toxic

effects on the aquatic environment and fish life (see Appendix I for definitions of "deleterious

substances"). In most instances, the control of these substances can be dealt with through an

awareness of their detrimental effects, the practice of good housekeeping (i.e. daily site clean-

ups, use of disposal bins, etc.) on the development project site, and the proper use, storage and

disposal of such substances and their containers. The following control guidelines should be

reviewed by the developer and construction contractor to ensure no deleterious substances are

released into fish habitat.

• Raw or uncured waste concrete and grouts should be disposed of by removal from the

development site or by burial on the site in a location and in a manner that will not impact

on a watercourse.

• Wash down waters from exposed aggregate surfaces, cast-in-place concrete and from

concrete trucks should be trapped onsite to allow sediment to settle out and reach

neutral pH before the clarified water is released to the storm drain system or allowed to

percolate into the ground (approximately 48 hours).

• Fuels, lubricants and hydraulic fluids for equipment used on the development site should

be carefully handled to avoid spillage, properly secured against unauthorized access or

vandalism and provided with spill containment according to codes of practice.

• Fuelling and lubricating of equipment onsite should only be done after the equipment to

be serviced is moved to a constructed service pad with a separate drainage collection

system, as far as possible from detention or sedimentation facilities and leave strips.

• Any spillage of fuels, lubricants or hydraulic oils should be immediately contained and the

contaminated soil removed from the site and properly disposed of in accordance with the

federal Department of Environment - Environmental Protection (DOE/EP) and the

provincial Ministry of Environment, Lands and Parks - Environmental Protection Division

(MOELP/EPD) requirements. Any spills should be reported immediately to DOE/EP

(phone: 666-6100) and MOELP/EPD (phone: 1-800-663-3456) for their counsel on

appropriate clean up procedures.

• Hydraulic fluids for machinery used for instream work should be biodegradable in case of

accidental loss of fluid.

• Waste oils and hydraulic fluids should be collected in leak-proof containers and removed

from the site for proper disposal or recycling.


42

• The rinse and cleaning water or solvents for glues, paints, wood preservatives and other

potentially harmful or toxic substances on the development site should be controlled so

as to prevent leakage, loss or discharge into the storm drain system.

• Gypsum board wastes must be removed from the project site, preferably to a recycling

facilities, or an approved disposal sites (disposal of gypsum board wastes by burying

onsite is not permitted).

• Wood wastes, such as hog fuel, sawdust and wood chips, are not acceptable for fill

material because of the potential release of toxic leachates from these wood wastes into

the aquatic environment.

• Where land is being redeveloped and there is contamination of the site, those

contaminants must be removed, disposed of, or otherwise neutralized, as prescribed by

DOE/EP and MOELP/EPD, prior to proceeding with redevelopment of the affected lands.

Potential mitigation and costs of contaminant removal are the responsibility of the land

owner.

Guidelines for Development of Site AccessSignificant release of sediments to the drainage systems and receiving waters can be caused by

site access development and lack of control during land development and building construction

activities. Included in the design of proper site access for minimizing potential impacts are:

• Construction site accesses should be restricted in number and to locations that will serve

as permanent access after development.

• Access pads and roads should be constructed prior to site area development, and in a

manner that will prevent the loosening of native subsoil.

• Access roads should be constructed or topped with a suitable coarse granular material

with a minimum of fines and clays. Non-woven geotextile is recommended as a

separation layer over the native subgrade. Organic topsoil should be stripped prior to

road construction if possible, and removed offsite or stockpiled.

• Wood wastes, such as hog fuel, sawdust and wood chips, are not acceptable for the

construction of access roads and support operations because of the potential release of

toxic leachates from these wood wastes into the aquatic environment.

• Runoff from the access roads should be collected via interceptor ditches or swales.

These flows should be routed to sediment ponds to allow the settling of sediments before

release to the drainage system.

• Sweeping of loose soils from surfaced streets is recommended over water flushing to

prevent soil entry into storm drains and the aquatic environment.


43

• Transport of excavated materials from the site should limit spillage on adjacent road

surfaces and dropping of loose soils in the form of dust or mud from wheels, tracks and

undercarriages of equipment.

Guidelines for Single Lot DevelopmentThe objectives during the development of an individual lot are to minimize erosion and release of

sediment offsite by controlling the development and construction activities. Single lot erosion and

sediment control measures include: planning the construction access; minimizing clearing and

grading activities; control of excavated soil stockpiles; surface and slope preparations; and

surface runoff control.

Site layout and Clearing

At the earliest stages, the individual lot development should be designed having regard to the

general principles of erosion and sediment control, specifically:

• Design and layout of the building site to minimize impervious areas.

• Retain existing vegetation and ground cover where possible.

• Schedule construction to dry months of the year.

• Restrict vehicle access and provide a surfaced working area.

• Minimize clearing and stripping of set backs and easements.

• Clearly mark building area and clearing boundaries onsite.

Soil Erosion Control

Surface soil erosion from individual lots and building sites is generated mainly from soil

excavations and graded areas. To minimize erosion onsite the following should apply:

• Cover temporary fills or soil stockpiles with polyethylene or tarps.

• Re-vegetate or final landscape disturbed areas as soon as practically possible.

• Limit machine access and operation to prepared access areas only.

Drainage and Sediment Control

Site drainage features can usually incorporate sediment control features to limit the offsite

transport of sediments directly into watercourses or into storm drainage systems that discharge

into watercourses:

• Divert runoff away from cleared areas by use of swales or low berms.

• Utilize silt fences around soil stockpiles and sloped areas.

• Collect runoff into site sediment traps prior to discharge offsite.

Figure 3.6 illustrates a typical lot development plan with erosion and sediment control features .


44

Figure 3.6 Single Lot Development Erosion and Sediment Control Features


45

SECTION 4STORMWATER MANAGEMENT

ObjectiveThe primary objectives of the stormwater management guidelines are to limit the post-

development 1:2 year storm offsite runoff rate to the predevelopment 1:2 year rate and to

maintain, as closely as possible, the natural predevelopment flow pattern and water quality in the

receiving watercourse. The clearing, grading and servicing of development sites within a

watershed alter the natural hydrology of the watershed. The increase of cleared and developed

areas decreases the ponding and transpiration of precipitation that previously provided detention,

which delayed runoff thereby reducing peak flows. The increase of impervious areas and routing

of stormwater flows decreases retention of precipitation by infiltration, which reduced the surface

runoff component thereby reducing total runoff volumes. With reduced detention and retention,

runoff can concentrate rapidly into significantly higher peak flows combined with increased runoff

volumes (i.e. longer periods of higher flows). This combination of hydrological factors can initiate

or accelerate channel and bank instability in receiving watercourses with negative impacts on fish

and fish habitat. In addition, due to reduced infiltration and local groundwater recharge,

baseflows during low flow conditions can be substantially lower than predevelopment baseflows,

reducing the amount and quality of habitat available to fish during these critical periods. These

flow-related impacts are often combined with:

• Decreased water quality resulting from pollutants and sediments introduced by the

surface runoff.

• Loss of habitat related to channelization and culverting of small streams.

• Destruction of wetlands and related riparian areas through drainage and development.

All these related impacts are typical of a disturbed, urbanized watershed, and result in a

reduction of the diversity and productivity of the aquatic habitat. As research, implementation

and assessment of stormwater management practices progress, the objectives of these

guidelines will be changed to reflect higher levels of downstream protection to protect fish and

fish habitat.

Selection of Stormwater Management TechnologyAt the earliest stage, stormwater management plans should be designed to maintain the

predevelopment flow pattern and volumes over the entire water season. Alterations in the stream

hydrology are often compounded by the diversion and re-location of flows by use of flow splitters

and inter-watershed stormwater connectors. The large-scale diversion and disruption of flows in


46

a watershed, including interception of baseflows and relocation of catchment areas, will not be

permitted where impacts to fish and fish habitat may occur.

In a developed environment, detention ponds and other runoff management technologies are

required to replace some of the natural processes that existed prior to development. They do not

completely replace the natural characteristics of runoff flow retention and detention, or water

quality buffering and sediment filtering. They are used primarily to detain flows, thus limiting the

peak rates of runoff from the developed site, provide some retention through infiltration and

recharge to groundwater flows, and remove some sediment carried by stormwater runoff. The

type of facility for a particular project should be based on the size of development, degree of

detention required and specific site conditions. Table 4.1 illustrates some of the advantages and

disadvantages of various stormwater management technologies. It should be recognized that

certain stormwater management technologies provide both water quantity and water quality

benefits. These runoff water quality objectives are also contained within these guidelines.

Where practical and cost-effective, it is expected that developers will implement technologies that

provide benefits to both water quantity and water quality to protect fish and fish habitat.

Stormwater Detention ObjectiveThe stormwater detention objective is to limit the post-development 1:2 year storm offsite runoff

rate to the predevelopment 1:2 year rate and to maintain, as closely as possible, the natural

predevelopment flow pattern in the receiving watercourse. The 1:2 year detention level has been

adopted by DFO and MOELP to account for the increase in impervious areas in developments

and understanding that environmental impacts (e.g. stream erosion, sedimentation; loss of

riparian habitat, stream channel changes, etc.) are occurring due to the more frequent, smaller

storm events. Detention requirements can be estimated by various methods: rational method,

SCS (U.S. Soil Conservation Service) unit hydrograph and level pool routing, as examples. The

selection of the method of analysis depends on the size of development and type of information

available, as well as the intended application of the results. Most analyses should be done or

reviewed by a Professional Engineer. Additionally, there are many computer software packages

available that aid in the analysis and design of these facilities, especially in the design of larger,

complex drainage and community detention systems. Methods for determining the required

degree of detention in the worked example are illustrations, not endorsements, of a particular

design method. Many regional and municipal authorities have specific runoff and detention

requirements. They will take precedence where they exceed the objectives of these guidelines.


47

Table 4.1 - Advantages and Disadvantages of Various Detention Technologies

Technology Advantages Disadvantages

Wet Ponds - good water quality buffering- excellent sediment removal- good for multiple use areas- good for aesthetics and park values- suitable for large detention volumes- good peak rate control

- high capital and construction costs- formal permanent facility- large land area used- poor runoff volume retention- possible insect control problems

Dry Ponds - good for multiple use areas- suitable for large detention volumes- good peak rate control- used in conjunction with infiltration

- poor water quality buffering andsediment removal

- large land area used- on-line better than off-line- empty ponds have poor aesthetics- high capital and construction costs

Wet Tanks orVault Detention

- good multiple use if covered/buried- good for building/rooftop runoff- use close to structures/foundations- good for built-up areas

- not suitable for large detentionvolumes

- poor for high sediment inflows- requires maintenance/clean-out- poor water quality buffering

Infiltration Systems - good water quality buffering- excellent small storm retention- excellent groundwater recharge- good peak rate control with detention- good for isolated developments- good for clean inflows (i.e. rooftops)

- not suitable for sediment inflows- poor in areas of high groundwater- high capital and construction costs- may require surface discharge- not suitable for large detention

volumes- not suitable for low permeability soils

EngineeredStormwater

Systems

- design into storm drain system- simple retrofit of existing systems

and catch basins

- may cause localized flooding- extra capital costs for system sizing

and orifice control manholes

CommunityDetention Facilities

- provide management for a largerarea

- share costs with municipality ornumber of owners

- good for aesthetics and park values- design into community plan

- possible re-routing of upstreamfeeder creeks in large communityfacilities

- construction during early stages ofdevelopment

- large infrastructure cost/responsibility- cost sharing may be difficult

Onsite DetentionFacilities

- design to suit built-up area- flexible for different requirements

- potentially larger total area used- potentially higher individual costs

ConstructedWetlands

- excellent water quality buffering- excellent sediment removal- good for aesthetics and park values- suitable for large detention volumes- excellent peak rate control- good groundwater recharge

- requires large area- high capital and construction costs- high maintenance costs- possible insect control problems


48

Stormwater Detention PondsThere are several types of detention ponds whose functions are the same, but which differ in

design and operation. Detention ponds generally provide temporary storage of runoff in the form

of a pond. The variation in pond type and operation allows the design to suit the size and type of

development. Dry ponds provide temporary detention by filling during storm events, and slowly

releasing runoff at a predetermined rate until empty. Because of the temporary nature of the

detention of the storm runoff, dry pond technology can be utilized in multi-use areas like playing

fields, parking lots, natural depressions, etc. Wet Ponds maintain a minimum level of water at all

times and provide detention by storing runoff above this permanent level. They release at a

predetermined rate down to the minimum water level. Wet ponds are a permanent structure

which can be featured within a developed area. With an on-line pond, all storm runoff passes

through the detention pond and the discharge is controlled to a desired predevelopment runoff

rate. With an off-line pond, only that portion of the storm runoff which exceeds the allowable

discharge, usually the predevelopment runoff rate, is bypassed and detained by the pond. That

volume detained is released when the runoff volume decreases below the predevelopment runoff

rate. Where the detention structure provides water quality benefits, on-line facilities are preferred

due to the fact that all flows are provided some level of treatment.

Design of Dry Detention PondsDry detention ponds are permanent facilities that remain after the development is complete, and

must be protected and maintained on a regular basis. The following are guidelines and

specifications for the design, construction and operation of dry detention ponds for these

guidelines (See Figure 4.1 for dry detention pond details).

Location and Number of Dry Detention Ponds

Dry detention ponds generally require a suitably sized area located at the lowest point in the

development area. The number of detention ponds required will be determined by the area

available for detention storage and the contributing catchment area.

Design Parameters for Dry Detention Ponds

• Design discharge rate predevelopment 2 year (1:2) storm runoff rate.

• Overflow spill capacity post-development 100 year (1:100) storm event.

• Emergency spillway capacity post-development 100 year (1:100) storm event.

Dimensions and Capacities of Dry Detention Ponds

• Maximum interior sideslopes 4H:1V.


• Maximum water depth in pond 1.0 meters.

• Minimum free board to top of berm 0.6 meters.


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• Ratio of effective length to effective width 5:1.

Inlet and Outlet Structures of Dry Detention Ponds

• A pretreatment sump to remove sediments in the runoff is required.

• Discharge and conveyance of pond flows should not cause erosion of natural drainage

systems.

• A spill control-type inlet and outlet structure is recommended as in Figure 4.3.

• Oil absorbent pads should be installed in the inlet and outlet structures.

Operation and Maintenance of Dry Detention Ponds

• The top of slopes or berms around sediment control ponds should be wide enough to


equipment and personnel.

• All interior surfaces of the pond should be protected from erosion and, where possible,

vegetated with suitable plant types to promote the removal of stormwater pollutants.

Stability and Public Safety of Dry Detention Ponds





• Discharge riser should be designed to exclude debris and large objects.

• The pond perimeter should be fenced, and have signs posted at intervals advising of the

maximum water depth and prohibiting water use for human consumption or bathing.


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Figure 4.1 Dry Detention Pond Plan and Sections


51

Design of Wet Detention PondsWet detention ponds are permanent facilities that remain after the development is complete, and

must be protected and maintained on a regular basis. The following are guidelines and

specifications for the design, construction and operation of wet detention ponds (See Figure 4.2

for wet pond details).

Location and Number of Dry Detention Ponds

Wet detention ponds require a suitably sized area generally located at the lowest point in the

development area. The number of detention ponds required will be determined by the area

available for detention storage and the contributing catchment area.

Design Parameters for Wet Detention Ponds

• Design discharge rate predevelopment 2 year (1:2) storm runoff rate.

• Overflow spill capacity post-development 100 year (1:100) storm event.

• Emergency spillway capacity post-development 100 year (1:100) storm event.

Dimensions and Capacities of Wet Detention Ponds

• Maximum interior sideslopes above active storage 4H:1V.

• Maximum interior sideslopes in active storage zone 7H:1V.

• Maximum interior sideslopes below active storage 4H:1V.


• Maximum water depth 2.5 meters.

• Minimum permanent storage depth 0.6 meters.

• Maximum permanent storage depth 1.2 meters.

• Maximum active detention storage depth 1.3 meters.

• Ratio of effective length to effective width 5:1.

Inlet and Outlet Structures of Wet Detention Ponds

• A pretreatment sump to remove sediments in the runoff is required.

• Wet pond has auxiliary water supply for make-up water to maintain minimum depth.

• Discharge of pond flows should not cause erosion of natural drainage systems.

• A spill control-type inlet and outlet structure is recommended as in Figure 4.3.

• Oil absorbent pads should be installed in the inlet and outlet structures.

• Pond outlet structure will contain provision for complete drainage.


52

Figure 4.2 Wet Detention Pond Plan and Sections


53

Operation and Maintenance of Wet Detention Ponds

• The top of slopes or berms around sediment control ponds should be wide enough to


equipment and personnel.

• All interior surfaces of the pond should be revegetated or protected from erosion.

• Pond outlet should draw deeper, cooler waters from pond to limit thermal effects of pond

on water temperatures. Riparian areas should be re-vegetated to provide shading to the

permanent pond area using plants of native species

• Pond outlet and outfall design should promote rapid re-aeration of pond discharges to

limit the potential for depressed dissolved oxygen content in receiving waters with fish

habitat.

Stability and Public Safety of Wet Detention Ponds





• Discharge riser should be designed to exclude debris and large objects.

• The pond perimeter should be fenced, and have signs posted at intervals advising of the

maximum water depth and prohibiting water use for human consumption or bathing.

Figure 4.3 Detention Pond Control Structure Typical Details


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Design of Detention Systems for Built-up AreasDetention of stormwater can be designed to fit into existing developments where space is limited

and construction of a conventional pond-type facility is not practical.

Roof Top Detention

• The use of roof top storage should be considered for industrial, commercial and

institutional buildings with flat roofs.

• Appropriate building code requirements covering rain loading must be followed (National

Building Code, 1990, Part 4, Commentary 1).

• The release rate from the roof top should be controlled by a roof top detention device.

Overflow scuppers should be provided at the maximum operating water level.

Parking Lot, Park Area and Work Yard Detention

Parking lots, park areas and work yard areas may be used for temporary water detention to

shallow depths. Generally, the flooded area operates like a dry pond where the runoff rate is

controlled by a valve or orifice located in an outlet pipe or manhole.

• The allowable depth is a function of safety and convenience to users and should be

designed accordingly. Flow control chambers should be used to control the water depth.

• Overflows to the storm drainage system, or a surface flood route, should be provided at

the maximum operating level.

Underground Detention Structures

Underground detention can be built into the design of stormwater systems by utilizing oversized

piping or off-line tanks controlled by a suitable device to limit outflow.

• Underground tanks, pipes or culverts may be used as detention storage facilities.

• All such underground facilities should have an access point for inspection and

maintenance. All underground tanks should have an air space, equal to 20% of the

maximum depth, connected to the atmosphere by a vent.

• The outlet structure should have a flow control orifice and overflow which is set at the

maximum operating water level (to pass storm runoff in excess of the two year (1:2)

storm event, and to provide an alternative outlet in the case of orifice blockage).

• Underground tanks: minimum of 0.5 meters cover and capable of CS-600 loads.


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Infiltration SystemsStormwater systems that utilize infiltration can provide many benefits to the hydrology and water

quality of an urbanized stream. Infiltration systems can provide retention of runoff through

groundwater recharge in addition to runoff peak flow control. The soil, through which the

stormwater runoff passes, acts as a filter removing a large percentage of the common pollutants

normally discharged to the stream or creek. Infiltration can provide recharge to the local area

groundwater which in turn feeds smaller streams and creeks. This groundwater is slowly

discharged back into streams and can constitute all or part of the stream's baseflow. Maintaining

this baseflow can be critical for fish and fish habitat during extended periods of little or no

precipitation and runoff. In many applications, stormwater runoff from the developed site can be

collected and discharged into an infiltration system where there is no infrastructure to support

conventional stormwater removal systems, with the added benefit of reduced costs of providing

offsite conveyance.

Application of Infiltration Systems

• Infiltration basins may be used as a method of stormwater detention only if required

detention volumes are relatively small.

• In larger applications, a series of infiltration basins may be necessary, each serving a

small collection area. Utilizing several galleries may reduce collection and piping costs

normally associated with conventional stormwater systems. Infiltration basins should not

be built under parking lots or other multi-use areas.

• Ponding and detention can be incorporated into the design of the infiltration system.

Conversely, infiltration can be used in combination with other detention technologies to

provide retention of runoff.

• Infiltration systems should not be used if any of the following site conditions are found:

• The seasonal high groundwater table is within 0.6 meters of the infiltrating

surface.

• Bedrock is located within 1.2 meters of the infiltrating surface.

• The infiltrating surface is located on top of fill material.

• The adjacent or underlying soils have a fully saturated percolation rate of less

than 0.5 inches per hour.

• The following conditions should be followed in siting an infiltration system:

• Subgrade foundation or basement is not located within 5.0 meters.

• A water supply well is not located within 30 meters.

• Infiltration systems should not be placed on slopes greater than 5H:1V due to

downslope seepage, saturation and slope failure potential.


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Design and Construction of Infiltration Systems

• The storage volume available is calculated from the effective porosity of the infiltration fill

material. The total void volume should equal the storage required for the two year (1:2)

design storm runoff associated with the developed catchment area.

• The 24 hour sustained saturated percolation rate should be used to calculate the basin

area requirement in order to drain the system within 2 days (48 hours). The basin bottom

area should be used as the infiltrating surface to calculate the required area.

• Provision for overland flow during frozen ground conditions or oversaturation should be

made.

• A pretreatment sump or vegetative filter should be used to limit sediment inputs into the

infiltration system and maintain its exfiltration capacity.

• Drain materials should be screened and washed, inert, natural gravels. The design void

space ratio can be calculated by measuring the volume of water required to fill a known

volume of drain rock (void ratios are typically 0.3 to 0.4 for a graded screened gravel).

• A good quality commercial filter fabric or geotextile should be used to completely

surround the drain rock. This minimizes migration of fines into the drain rock,

maintaining the void volume required for storage of the runoff. A suitable geotextile is a

non-woven, synthetic, needle punched polypropylene.

• Minimum permeability 1.2 x 10-2 cm/s.

• Minimum grab tensile strength 750 N.

• Equivalent opening size 0.125 mm.

• See Figure 4.4 for the application and design of a small infiltration system.


57

Figure 4.4 Infiltration System Design and Typical Application


58

Oil-Water SeparatorsOil-water separators are suitable for the removal of floatable petroleum-based contaminants from

small areas of concentrated activity, such as gas stations, automotive service areas and parking

lots. Oil-water separators have a limited ability to remove floatable petroleum contaminants in

typical large-scale stormwater runoff applications and their application should be limited to these

small area generation sites. Removal of these contaminants is best achieved using a coalescing

plate oil/water separator (CPS). The coalescing plate separator uses a packed plate media and

is effective in removing oil droplets 60 microns and larger, which constitute up to 85% of the oil

volume in commercial applications (Gibb et al., 1991).The required area and number of plates are

determined by the design inflow into the CPS unit.

• The design flows into the separator should be based on the 1:2 year post-development

flows, when the detention requirements of these guidelines are not provided for the

catchment area.

• Where detention is provided to the 1:2 predevelopment flow rate, the oil-water separator

should be installed downstream of the detention structure.

• Spill control separators (similar to Figure 4.3) also limit the impact of uncontrolled spills of

pollutants, and should be installed as required in storm drainage catch basins.

• Oil absorbent pads should be installed to aid in the removal of floatable petroleum

contaminants. The absorbent pads should be replaced on a regular basis and disposed

of in a safe manner

Figure 4.5 Coalescing Plate Oil-Water Separator


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Stormwater Runoff Water Quality ObjectivesThe changes in land use, increase in impervious area, and introduction of pollutants related to

human activity all contribute to reduced water quality impacting fish and fish habitat. Currently,

the Fisheries Act regulates the general discharge of deleterious substances into waters

containing fish or fish habitat (see Appendix I for definitions of "deleterious substances"). Future

guidelines and regulation by MOELP, DOE and DFO of stormwater runoff water quality and

discharges are expected within the next generation of these guidelines (e.g. the development of

best management practices, technologies and regulated contaminant levels). References

included in the back of these guidelines are sources of additional information stormwater runoff

water quality management techniques and technologies.

Stormwater Runoff Water Quality Best Management PracticesWhere stormwater runoff water quality objectives are required for receiving water quality, and

protection of fish and fish habitat, the following stormwater management strategies should be

implemented as best management practices (BMP). BMPs are physical, structural or

management practices that reduce or prevent water quality degradation. Source control remains

a key method for reducing introduction of pollutants, such as toxic/hazardous materials, organic

and inorganic contaminants, resulting from human land and water use, or spills, especially in the

commercial and industrial environments. Without source control, runoff water quality standards

are limited by the effectiveness of expensive treatment technology.

Source Controls

Education and information regarding the problems and potential solutions of stormwater pollution,

and its impact on the fisheries resource and environment, should be presented to the public.

Programs and alternatives to eliminate the use or production of deleterious substances should be

promoted (e.g. leaded gasoline). Practices to remove materials from the environment before

interception and transport by precipitation runoff or through the storm drainage system should be

adopted (e.g. enhanced street sweeping, covered parking areas). Land and water users should

adopt a watershed planning process with DFO and MOELP to avoid potential conflicts with the

fisheries resource.

Treatment Controls

Treatment controls should be designed on a site-specific basis, after examining the alternative

treatment technologies, and selecting the best available based on cost and effectiveness. These

controls should be designed and constructed, with monitoring of the operation and performance

of the technology, as well as the impact on receiving water quality.


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Stormwater Runoff Water Quality Best Practical TechnologiesSeveral technologies have the ability to provide both water quality benefits and runoff control.

Water quality benefits are based on contaminant removal mechanisms using biological and

physical processes. Runoff control is provided by improved detention and retention of

stormwater flows for reduction in peak runoff rates and volumes of runoff. The following

stormwater treatment technologies should be implemented as best practical technologies

(BPT). BPTs are technologies that provide cost-effective contaminant removal and treatment.

Wet Detention Ponds

Permanent wet ponds can provide deleterious substance removal through biological activity:

uptake and conversion by plants, microbial degradation, and by physical processes:

sedimentation, filtration, absorption and adsorption. In addition, wet ponds can provide

detention/retention requirements of stormwater flows. As a general guideline for water quality

design, the permanent pond should have a minimum surface area equal to 1.5% of the

catchment area and have a permanent pond volume equal to the design storm runoff volume.

Design parameters also include: vegetation types (floating, emergent and submergent

vegetation) and area coverage, water depth and area coverage, and detailed pond operation

parameters.

Infiltration Systems

Infiltration systems can provide retention of highly contaminated initial flows (i.e. "first flush"

events). Physical removal of deleterious substances by filtration and adsorption, as well as

conversion of soluble pollutants by bacteria, occurs within the infiltrating soils. It is possible to

use infiltration in conjunction with other technologies (e.g. detention ponds) to meet water quality

and quantity objectives.

Constructed Wetlands

Wetlands can be constructed specifically to treat stormwater runoff and provide similar biological

and physical removal mechanisms as found in wet permanent ponds. Constructed wetlands can

also provide buffering and retention of runoff flows. Constructed wetlands are treatment

systems, but can also provide additional benefits for aquatic and wildlife habitat. The use of

existing natural wetlands to provide stormwater treatment is not acceptable. General design

requirements for constructed wetlands include: vegetation types and area coverage (floating,

emergent and submergent vegetation), water depth and drainage design. Vegetation

management, including fall harvest of plant growth, should be considered to prevent release of

nutrients and BOD related to vegetation decomposition. As a general guideline for water quality

design, the constructed wetland should have a minimum surface area equal to 1.5% of the

catchment area.


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Biofilters

Biofilters are vegetated filter strips and swales that provide physical removal of deleterious

substances, notably particulate contaminants, with some biological removal mechanisms.

Biofilter technology is suitable for sheet flow runoff, typical of large linear impervious

developments like roadways and parking lots.

Urban Forests and Leave Strips

Depending on the extent of tree canopy and ground cover retained, runoff reduction and

deleterious substance removal can be achieved by the use of forested areas. Removal

processes include filtration, absorption, and biological uptake and conversion by plant life.

Riparian leave strips, especially surrounding aquatic habitat, promote the conservation and

protection of fish and wildlife habitat.

Guidelines for Implementation of Stormwater Water Quality Objectives• Use the best management practices (BMP) and best practical technology (BPT) for

control of stormwater runoff water quality where runoff has detrimental impacts on fish

and/or fish habitat.

• Use technologies that provide both physical and biological removal of contaminants, in

addition to detention and retention of stormwater runoff.

Storm Drain Marking ProgramThe marking of curbside storm drains with bright yellow fish is to remind people that most drains

empty into a nearby creeks that likely contains fish habitat. Local community groups and schools

across B.C. are involved in the program, initiated by DFO and MOELP, to encourage

understanding of the effects of urbanization and stormwater pollution on our local streams and

their fish populations. Information on the storm drain marking program can be obtained from your

local DFO or MOELP office. Information pamphlets and storm drain marking should be initiated

in all new developments where runoff drains into streams containing fish habitat.


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63

SECTION 5INSTREAM WORK

ObjectiveIt is recognized that at times it may be necessary to perform instream work as part of the process

of developing land. The objective of the instream work guidelines is to promote careful planning

and construction practices to limit the potential for impacts on the aquatic environment. Instream

work is any work performed below the high water mark, either within or above the wetted

perimeter, of any feature within the FSZ. Prior to commencement of any instream work

and with sufficient lead time, proponents should consult with DFO/MOELP for

information regarding FSZ species timing windows and construction methods .

Because instream work has the potential to be extremely destructive to fish habitat, methods and

procedures to minimize instream activities should be considered during the planning and design

stages of a project. The procedures should be specifically designed to achieve the following

objectives throughout the project.

• Protect the natural stream conditions and structure to promote stability of bank and bed

structures, and retain riparian vegetation.

• Provide the instream conditions required for unhindered fish passage upstream and

downstream.

• Prevent introduction of pollutants and deleterious substances by controlling construction

activities and site conditions.

• Prevent generation of sediment, impacting fish and aquatic habitat, by utilizing the proper

instream construction technique and supervision.

Guidelines for Instream WorkGeneral guidelines for instream work include:

• Consult with local DFO/MOELP staff regarding presence, distribution and timing of

migrations of fish species in the stream or watercourse, and FSZ window (Appendix III).

• Plan instream work for periods within the confirmed FSZ window that will minimize

disturbance and impact on fish and fish habitat.

• Plan instream work for periods of suitable stream and environmental conditions,

determined in consultation with DFO/MOELP.

• Minimize the duration of the instream activities.

• All material placed within the wetted perimeter must be coarse, non-erodible, and non-

toxic to fish. Do not remove gravels, rock or debris from any stream without the approval

of DFO/MOELP.


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• Minimize disturbance to stream banks where equipment enters and leaves the

watercourse. Reconstruct and revegetate stream banks to their original condition as

soon as activity has finished (see Section 2).

• Use the proper equipment for the proposed construction activity. Avoid damage caused

by stuck equipment or delays because of insufficient capacity for proposed work.

• Ensure that all construction equipment is mechanically sound to avoid leaks of oil,

gasoline, hydraulic fluids and grease. Consider steam cleaning and check-up of

construction equipment prior to use instream.

• Require the use of biodegradable hydraulic fluids for machinery used for instream work.

Timing of Instream WorkIt must always be assumed that fish are present in a watercourse since the utilization and

residency times for different species vary widely in accordance with their spawning and rearing

cycle requirements. The windows of allowable times when instream work can be tolerated are

often based on the reduced sensitivity of the fish to disturbances rather than the absence of fish

during these times. The work should be coordinated and timed so that conflict with the fish

populations is minimized. Appendix III contains information on the species-specific freshwater

FSZ timing windows. The utilization of various habitats (freshwater lakes, rivers, estuarine and

marine environments) by both resident and anadromous fish populations place restrictions on

instream work. Timing windows of allowable instream work should always be

confirmed with DFO/MOELP personnel responsible for the local area in which the

proposed development is located . Site specific differences exist and DFO/MOELP staff

should be consulted early as possible in the planning process.

Instream Work and Construction PracticesMethods such as sheet pile isolation, coffer damming, fluming and stream diversion are often

acceptable temporary containment practices to minimize aquatic disturbance during instream

construction. Instream containment and dewatering at work sites located within fish bearing

streams are commonly required for instream construction. Isolation from flowing water is usually

a requirement for maintaining water quality. When dewatering of the site is required, this work

should proceed in the presence of a DFO/MOELP representative or Environmental Monitor who

should make the final decision regarding the need for a fish salvage program. Should a salvage

program proceed, the proponent shall assist in the recovery of fish and the transporting of them

to a safe area outside the influence of the work site.

Coffer Dams and Sheet Piling

Coffer dams and sheet piling are used to isolate the work area from the aquatic environment and

limit the disturbing activities associated with construction activities. They should not reduce the


65

stream width by an amount that will lead to erosion of banks both upstream and downstream of

the site or impede the movement of migrating fish. Only clean, silt free materials shall be used

as the fill materials for coffer dams, and all bags and materials must be removed after

construction is completed. All water pumped from contained work areas within coffer dams must

be discharged on an upland site to allow sediment removal before it re-enters any watercourse.

Flumes

Flumes are most often heavy gauge steel pipe(s) that will carry the flowing water over the total

distance of the isolated work site. The fluming pipes should be sized to handle the maximum

expected discharge recognizing the maximum practical fluming capacity is about 3 cubic meters

per second (106 cfs). The design of the flume should include consideration of the flow capacity,

size and length of fluming, area and depth of excavated area, and stability of the stream bed

substrate during excavation.

Temporary Stream Diversions

Temporary stream diversions or channelization should always be excavated in isolation of stream

flow, starting from the bottom end of the diversion channel and working upstream to minimize

sediment production. Any dewatering flows should be directed to a settling pond to remove

sediments. Channel diversion shall only commence in the presence of a DFO/MOELP

representative and should be completed as quickly as possible, preferably within a single day

during the low flow period. Upon completion of the instream work, the stream shall be restored to

its original configuration and stabilized to prevent bank erosion around the temporary diversion.

Water Intakes

Water intakes in fish bearing streams shall be screened to Federal Fisheries specifications to

prevent the possibility of juvenile fish mortality. For detailed information refer to DFO's Fish

Screening Directive (1990).

Construction Materials and Instream WorkSpecial care is required in the use of some common, but highly toxic, construction materials in

and around areas of instream work. Wood preservatives, paint and concrete are potential

contaminants frequently used near watercourses.

Wood Preservatives

Wood preservatives containing chemicals such as creosote, chlorophenols and zinc or copper

napthanate solutions are extremely toxic to aquatic organisms. However, based on information

on mobility, persistence, and aquatic toxicity, it is suggested that CCA (chromated copper

arsenate) treatment is rated as the preferred wood preservative treatment in freshwater

environments, and creosote is the preferred wood treatment in marine environments. With CCA

treatments, the treated dry wood should be rinsed after application and drying, with wash waters


66

contained or recycled, and weathered or seasoned for a minimum of 45 days before it is used in

or near any water body. Pressure treated lumber containing CCA should be allowed to fully react

and also weathered for a minimum of 45 days. Application of treatment solutions to installed

materials on or over water is not recommended under any circumstances. Creosote applications

should include steam treating to reduce loss of preservative into the marine environment.

Paints

All paints are toxic and should only be applied when tarpaulins have been installed beneath work

areas. This will allow for the collection of any excess liquid or scrapings and the subsequent

careful removal to a safe disposal location. Paint removal scrapings and sandblasting slag

should also be contained.

Cast-In-Place Concrete

Concrete, which contains lime in the cement, can kill fish by substantially altering the pH in

stream water. All cast-in-place concrete should be totally isolated from flowing water for a

minimum 48 hour period to allow the pH to reach neutral levels before continuing instream work.

Pre-cast concrete should be used whenever applicable for the construction required.

Sediment and Erosion Control during Instream WorkSediment Control

The temporary containment and removal of sediment-laden water will probably be necessary

during instream work, even when isolation techniques are used. Contaminated water within the

work site must be pumped onto a land site where it will not re-enter the creek, or will do so only

after filtration and settling has taken place.

Instream Machine Crossings

Where no alternate access to the opposite side of a watercourse exists, where it is impossible to

do certain instream work from the banks, or where it is not feasible to isolate a worksite during

construction, it may be necessary to take machinery and/or equipment into or through a flowing

stream. In such situations, the local fisheries agencies must be consulted beforehand. Access

should be arranged for the period of flow with the least impact to fish and fish habitat. All

vehicles and equipment must be clean and in good repair to avoid leakage of petroleum products.

Access by fording should be restricted to one crossing location, and traffic should be limited.

Instream control measures and engineered roads using clean fill materials may be necessary.

The access site must be chosen with care, where banks are low, the stream substrate is suitable,

and the water shallow. Upon completion, the banks should be restored, restabilized and

revegetated to prevent erosion.


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Erosion Control and Streambank Rehabilitation

Any time a bank or the channel bottom is disturbed, restorative action should be taken to prevent

erosion, siltation and to replace lost fish habitat. If adequate site selection and careful

construction techniques are implemented, minimal disturbance and rehabilitation should be

required to the riparian zone and the stream. Each site needs to be assessed individually at the

planning stage to determine what rehabilitation will be needed. Erosion control materials should

not encroach into the stream's cross-sectional width. Encroachment can create backwatering

(flooding) and increase stream velocities that may cause scouring and erosion. It may be

possible to reuse excavated materials. In some cases, however, they may have to be totally

replaced with materials more suitable for fish habitat (i.e. using washed, silt-free gravel as

backfill). Acceptable bank erosion control methods include hand seeding, hydroseeding, silt

blankets, rock riprap and revegetation using plantings. Scalping existing instream material, like

gravel bars or large rocks, will not be permitted. The top of banks and the riparian zone may also

need to be stabilized, commonly by planting trees, shrubs, and various bushy types of vegetation.

Native species should be used for all revegetation projects.

Explosives

The use of explosives in or near fish habitat must be approved by DFO/MOELP. Each

application will be considered individually on the site specific conditions and circumstances.

Explosives may only be used when other, less detrimental, methods are not feasible. Some

general considerations to consider are:

• Schedule blasting for periods when fish are not present in the blast influence area.

• No blasting should take place near known spawning areas when eggs or alevins are still

in the gravels.

• Minimize blast energy by using low velocity charges, multiple charges and special

detonation techniques.

• Minimize damage to surroundings by the use of blasting mats and blast deflectors.

In some situations, it will be necessary to physically remove juvenile salmonids from, and block

their re-entry back into, the blast zone. The underwater blast zone generally encompasses the

area within a 400 meter radius of the detonation site depending on blast energy and materials.

The proponent or developer must conduct such removal activities only with the direction and

assistance of a qualified professional biologist. Information on explosives use can be found in

Munday et al. (1986).


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Maintenance of Instream StructuresWell designed and constructed instream structures should require minimum maintenance.

Frequent inspections, particularly during high runoff periods, are very important. Improper

functioning of a structure during or after a major storm event may indicate the need for minor

repairs or modifications. It is advisable to perform such minor repairs immediately in order to

prevent the need for major repairs later, and to ensure safety and reduce the environmental

impact. General maintenance should be carried out according to an agreed schedule of works

and agency contact procedure. If emergency measures are required, only justifiable essential

preventative actions should be taken to protect life and major losses of property. If time allows,

contact the fisheries agencies before carrying out emergency repairs.

Permanent Watercourse Diversion or RelocationThe permanent diversion or relocation of streams or watercourses is strongly discouraged and

only in unusual circumstances will it be considered by DFO/MOELP. Where a permanent

diversion or relocation is absolutely necessary, a compensation diversion channel shall be

designed in detail under the guidance of a fish biologist and other specialists. This compensation

habitat is to provide no net loss of the productive capacity of the aquatic fish habitat. The

diversion or relocation must display hydraulic similarity to the existing stream or watercourse in

order to ensure minimum morphological change to the stream reach. This requires careful

evaluation and cataloguing of the existing features in advance of the relocation design. The

construction of the compensation channel shall be carried out in dry conditions without

connection to the existing stream or watercourse. Once the construction is completed and

revegetation has been established, the connection to the existing watercourse, downstream and

upstream of the diversion or relocation, will be permitted. The connection shall be made only

during the approved timing windows for instream work and under DFO/MOELP supervision.

Sufficient notice shall be provided to the local DFO/MOELP offices to permit reconnaissance,

planning and inspection of the diversion before connection to the stream takes place. The

proponent will provide the means and expertise to relocate resident fish stocks from the section

of stream or watercourse to be abandoned to the new section being brought into service. This

relocation shall be carried out quickly and with a minimum of stress to the fish stocks once the

connection work is finished and the new stream reach has stabilized to a degree acceptable to

the DFO/MOELP. Re-inspections and evaluations of the success and effectiveness of the

diversion or relocation shall be made at specified intervals after its placement into service, and

the necessary corrections and adjustments made by the development proponent where such are

deemed necessary by DFO/MOELP personnel. A formal written agreement will be necessary

between the developer and DFO/MOELP, setting out the detailed conditions of approval.


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SECTION 6FISH PASSAGE AND CULVERTS

ObjectiveThe objective of these guidelines is to maintain migratory fish movements in watercourses to

ensure that the various phases in the life cycle of fish can be carried out without undue stress or

hazards that would affect the productivity of present and future populations. Barriers that prevent

fish from moving upstream to spawning or restrict access to rearing and feeding areas can take

many forms which may not be obvious. They include: dams of materials and debris, increased

flow velocities over long reaches of stream, lack of jump pools at drops in the stream channel and

insufficient water depth because of sedimentation or channelization. Natural migratory fish

movement should be maintained by the provisions of these guidelines which are intended to

minimize changes to the natural stream morphology and hydraulic conditions, and maintain

adequate water quantity and quality.

Natural Fish MigrationFish migration occurs in response to a need, whether to spawn and reproduce, find food items

and feed, or to escape predators. The migration event may involve a large or small population of

individuals moving over a short or prolonged time period, up or downstream. Where the various

lifestages of fish migrate naturally, the stream flow conditions, hydraulics and morphology provide

a certain set of conditions suitable for their passage. Development should have no impact on

that natural set of predevelopment conditions. Blockages and delays in migration, whether

caused by complete or partial obstructions, can have devastating effects on a population of fish.

Various permanent and temporary structures are constructed to allow the passage of vehicles

and people over streams, lakes and rivers. Where options exist for the type of structure to be

used, a spanning bridge which maintains the natural bank and bed structure is preferred from a

fisheries perspective. Clear span bridging permits the retention of riparian vegetation around the

crossing site owing to a small footprint (area covered by the structure's footing and fill) on the

crossing area. Bridges allow unrestricted movement of bed load by maintaining the natural

stream bottom and bed structure. Additionally, bridging allows free passage of salmonids at

various water levels by maintaining the natural hydraulic conditions that existed before

development. Encroachment of piers and footings can impact the stream by reducing the wetted

perimeter causing local scour of the bed and erosion of the stream banks. Table 6.1 illustrates

the preferred ranking of crossing structures as well as some of the associated design and

fisheries-related features.


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Table 6.1 - Fisheries and Design Considerations for Stream Crossing Structures

TYPE OF STRUCTURE FISHERIES CONSIDERATIONS DESIGN CONSIDERATIONS

BRIDGE - Can retain existing bottom substrate,bank structure and riparian vegetation.

- Does not alter LOD or bed loadtransport capacity of stream reach.

- Can retain natural fish passage streamqualities.

- No limit to stream hydraulic capacity ifencroachment of piers or footings islimited.

- Ability to cross large streams andrivers.

- Structure can be designed with noinstream work required.

OPEN BOTTOM CULVERT - Does not limit fish passage if properlydesigned and constructed.

- Retains natural stream substrate.

- Water velocities are not significantlychanged if as wide as the naturalstream.

- Loss of riparian vegetation because ofinfilling around culvert.

- Design to normal stream width.

- Can be placed in multiple units toprovide wider section and larger endarea.

- Provide suitable footing for wallsection to prevent undermining bystream erosion.

BOX CULVERT - Can limit fish passage at low flows byreduced water depth in culvert (with nobaffles).

- Baffles can be easily installed toprovide fish passage.

- Wide bottom area allows retention ofbottom substrates.

- Can be designed to maintain normalstream width.

- Can be placed in multiple units toprovide wider section and larger endarea.

- Precast units can be installed quicklylimiting instream construction time.

PIPE ARCH CULVERT - Can limit fish passage at low flowsdue to reduced water depth in culvert(with no baffles).

- Baffles can be installed to provide fishpassage.

- Wide bottom area allows retention ofbottom substrates.

- Wide bottom area provides good flowcapacity with limited depth increase.

- Good for low clearance installations.

- Multiple units can be installed toprovide greater capacity.

- Reduced depths at low flows mayrequire backwatering.

STACKED CULVERTS - Can provide fish passage over a widerrange of flows, depths and watervelocities than a single culvert.

- Fish passage must be provided inlowest culvert for low flow conditions.

- Possible to backwater lowest culvertto reduce velocities and allow fishpassage.

- Same hydraulic properties as a singleculvert.

- Flows may be excessive in singleculvert at low flow conditions.

- Lowest culvert may plug with bed loadif culvert grade is unsuitable.

ROUND CULVERT - Difficult to provide passage in smalldiameters.

- Concentrates flow and velocities.

- Generally poor for fish passagesituations.

- Loss of habitat because of infillingaround culvert as with all fill structures.

- Concentrates flows and increasesvelocities and potential scour at highflows.

- Reduced depths at low flows mayrequire backwatering.

- Can have poor bed load transportthrough culvert.


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Culvert Design and InstallationCulverts, when properly designed and installed correctly, may have little impact on fish migration.

Culverts are ideal for low volume, intermittent or ephemeral streams, or high gradient streams

with no fish migration or fish habitat values. Their use for major crossings, large streams or

streams with high fish habitat values is discouraged. Due to the lack of detailed streamflow data

for small streams, and the wide variation in the timing of upstream migration of fish in different

watersheds, it is important that an adequate hydrological analysis and culvert design be

undertaken. To ensure the fisheries resource is not adversely affected by interruption of

upstream migration at a culvert and access to habitat is provided, certain conditions must be

maintained at the culvert. These conditions include: minimizing culvert lengths, provision of

outlet pools and baffles, maintaining minimum water levels, and limiting culvert grades and water

velocities. DFO/MOELP staff should be contacted if provision for adult or juvenile

passage is required at a development site .

Figure 6.1 illustrates poor culvert installation limiting fish passage upstream. The small, round

culvert lacks adequate baffling for low flows, and would have excessive velocities at high flows.

The outlet conditions do not provide ready access to the culvert from the outlet pool resulting in

severely restricted access for upstream migration.

Figure 6.1 Culvert Installation Limiting Fish Access


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Figure 6.2 illustrates the application of fish passage requirements to the same culvert shown in

Figure 6.1. The round culvert has been replaced with a concrete box culvert with baffles installed

to aid upstream passage. A small fishway has also been installed to allow ready access from the

stream to the culvert outlet.

Figure 6.2 Culvert Providing Upstream Fish Passage

Multiple Culvert InstallationsWhen more than one culvert is provided at the same site, fish passage criteria need only be

applied to one of the culverts. That culvert to which fish passage criteria are applied should be

installed at least 0.31 meters lower than the other culvert(s). Often the installation of culverts at

different elevations will provide fish passage over a range of water levels and hydraulic

conditions.


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Passage Design Criteria for Adult FishGenerally, migrations of adult fish are upstream spawning migrations required to continue the life

cycle of the population. Where culverts are used and upstream fish migrations occur, culvert

design should include features and design to allow the free passage of adult fish. Culvert design

should take into account their upstream swimming capabilities (Table 6.2) as well as design

criteria for fish passage requirements. The following is a summation of criteria for adult fish

passage from Fisheries and Marine Service Technical Report #811 (Dane 1978).

• The diameter of a culvert used in any watercourse providing for the passage of fish

should not be less than 0.45 meters.

• The average water velocity in the culvert should not exceed the following values:

• 1.2 m/s for culverts less than 24.4 meters in length

• 0.9 m/s for culverts greater than 24.4 meters in length

• for culverts greater than 61 meters in length, special consideration will have to be

given on a site specific basis by DFO and MOELP.

• The depth of water should not be less than 0.23 meters at any point within the culvert.

• Any sudden drop in the water surface profile at any point within the culvert influence

should not exceed 0.31 meters.

• During the period of upstream fish migration, the length of time during which the

foregoing conditions are not met at the culvert site should not exceed 3 consecutive

days in an average year.

• All culvert facilities through which salmonid migration occurs should be designed to

accommodate the 100 year flood (1:100), which is defined as that estimated discharge

event having a recurrence interval of 100 years.

• During the design flood event, the headwater depth (HW) measured at the upstream end

of the culvert should not exceed the height or diameter (D) of the culvert.

• The effective slope (mean slope of the water surface from the culvert inlet to the tailwater

control point) of the culvert should not exceed:

• 0.5% for a culvert greater than 24 meters in length, unless baffles are added

• 1.0% for a culvert less than 24 meters in length, unless baffles are added

• 5.0% at any time, even with the addition of baffles.

• The culvert should be installed so that it has a constant slope through its length, except

for an appropriate camber allowance where settlement is anticipated.

• The culvert should be installed so that the bottom (invert) is at least 0.31 meters below

the grade line of the natural bed of the stream.

• An outlet pool with tailwater control should be provided at the culvert exit.


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Passage Design Criteria for Juvenile FishBarriers often block access to rearing areas utilized by juvenile fish. These rearing areas, often

small creeks, channels and ditches, are critical habitat and are often made inaccessible by

improper culvert installation. Generally, fry and juvenile fish have limited swimming capability, in

comparison to adults of the same species, with swimming speeds proportional to their body

length. While the majority of juvenile fish migrations are downstream, juvenile fish may move

upstream in search of food items, to escape predators or to avoid unsuitable stream conditions

(e.g. in nature, certain races of sockeye salmon fry and lake-outlet spawning rainbow trout fry

swim very close to the shore or bottom utilizing the small eddies and channel roughness in order

to move upstream to lake rearing areas). Additionally, migrations of juvenile fish are difficult to

detect because they may occur during darkness and in lower densities in comparison to adult

migrations. Presence and access to juvenile fish habitat is often overlooked. This important

habitat may include swampy areas, wetlands, small streams and side channels or intermittently

wetted areas

Figure 6.3 Culvert Installation for a Small Creek with Provision for Fry Passage


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Table 6.2 - Sustained, Prolonged and Burst Swimming Speeds For Various Fish

Species and Life Stage(size - mm)

Sustained*Speed(m/s)

Prolonged*Speed(m/s)

Burst*Speed(m/s)

Coho: AdultsJuveniles (120 mm)Juveniles (90 mm)Juveniles (50 mm)

0.0 - 2.7 2.7 - 3.20.4 - 0.60.3 - 0.50.2 - 0.4

3.2 - 6.6

Sockeye: AdultsJuveniles (130 mm)Juveniles (50 mm)

0.0 - 1.00.0 - 0.50.0 - 0.2

1.0 - 3.10.5 - 0.70.2 - 0.4

3.1 - 6.3

0.4 - 0.6

Chinook: Adults 0.0 - 2.7 2.7 - 3.3 3.3 - 6.8

Steelhead: Adults(Use Rainbow Trout juvenile data)

0.0 - 1.4 1.4 - 4.2 4.2 - 8.1

Rainbow Trout: AdultsJuveniles (125 mm)Juveniles (50 mm)

0.0 - 0.90.0 - 0.380.0 - 0.15

0.9 - 1.80.38 - 0.750.15 - 0.3

1.8 - 4.30.75 - 1.130.3 - 0.45

Brown Trout: AdultsJuveniles (>75 mm)

0.0 - 0.70.0 - 0.6

0.7 - 1.9 1.9 - 3.9

Cutthroat Trout:Adults(Use Rainbow Trout juvenile data)

0.0 - 0.9 0.9 - 1.8 1.8 - 4.3

Arctic Char: Adults 0.6 - 1.1

Arctic Grayling: Adults 0 - 0.8 0.8 - 2.1 2.1 - 4.3

Whitefish: Adults 0 - 0.4 0.4 - 1.3 1.3 - 2.7

Walleye: Adults(230 - 410 mm)

0.0 - 1.1

Carp: Adults 0 - 0.4 0.4 - 1.2 1.2 - 2.6

Suckers: Adults 0 - 0.4 0.4 - 1.6 1.6 - 3.1

* Sustained speed can be maintained indefinitely.

Prolonged speed can be maintained for up to 200 minutes.

Burst speed can be maintained for up to 165 seconds.

(Katopodis, 1991)


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Outlet Pool and Tailwater ControlAn outlet pool and tailwater control should be constructed at the downstream end of the culvert to

maintain the desired water level within the culvert and backwater the culvert at higher flows to

reduce the culvert velocities. See Figure 6.4 for details of a rock outlet pool with tailwater control.

• The dimensions of the outlet pool can be varied to create specific hydraulic conditions in

response to unusual site constraints. Usually, the recommended width of the pool

approximates the natural width of the stream, and the sides will coincide with the stream

banks, which can be appropriately armoured to prevent erosion. The bottom elevation of

the pool should be at least 0.61 meters below the invert elevation of the culvert at the

outlet.

• A tailwater control device should be constructed at the downstream end of the outlet pool

to provide a minimum depth of 0.23 meters throughout the culvert during the lowest

condition of stream discharge anticipated at the site, or at least 0.23 meters above the

lowest elevation in the culvert.

• The tailwater/outlet pool should reduce velocities in the culvert barrel or at the entrance

to the culvert by backwatering.

• A low flow channel or notch, 0.61 meters wide and 0.31 meters in depth, in the tailwater

control structure should be provided and should extend downstream connecting with the

deepest part of the natural stream bed.

• The outlet pool should control erosion at the downstream end of the culvert by dissipating

the energy of the flow and provide a transition zone between the culvert and the natural

stream channel.


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Figure 6.4 Diagram and Photo of a Rock Outlet Pool and Tailwater ControlStructure


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BafflesCulvert baffles are flow interference structures, usually in the form of low weirs, which extend

partially or entirely across the culvert cross-section. Such structures either interrupt the flow

pattern and provide the fish with a series of resting areas or create a continuous zone or route of

controlled velocities through which the fish can swim.

• Baffles should be constructed in the culvert barrel if the slope of the culvert exceeds the

criteria outlined in Passage Design Criteria for Adult Fish.

• The most successful baffle configuration has been the offset baffle design, developed

and model-tested by McKinley and Webb (1956). The offset baffle configuration consists

of 'paired' baffles attached to the sides and bottom of the culvert and extending out into

the flow of water. The baffles produce a flow pattern compatible with fish migration while

minimizing interference with debris or bed load movement (see Figure 6.5 for general

layout dimensions for offset baffle arrangement).

• Baffles significantly reduce the hydraulic efficiency of the culvert. When making capacity

calculations, the reduced efficiency can be estimated by subtracting the cross-sectional

area displaced by the baffles from the cross-sectional area of the culvert, and increasing

the roughness coefficient.


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Figure 6.5 Diagram and Photo of Typical Culvert Baffle Layout and Installation


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SECTION 7IMPLEMENTING THE LAND DEVELOPMENT GUIDELINES

ObjectiveThis section deals with the steps, procedures and items required to prepare a land development

impact assessment in order to substantiate the practical implementation of the guidelines for

DFO and MOELP fish habitat impact assessment purposes. This document should be part of the

overall development plan and be included in the development/construction specifications.

Recognition by the land development proponent of the impacts on the aquatic environment that

may be created by the project is one of the most important steps in preventing the loss of fish

spawning, incubation and rearing capability in streams and watercourses. The land development

proponent should "take stock" of the natural conditions prevailing in waters on and adjacent to the

site, prior to the commencement of any work. This will create an awareness, and respect for this

resource and a recognition of the necessity and responsibility to preserve it.

The planning process provides both the agencies and the proponent a framework to assess

development activities, potential impacts and effects of the proposed control measures. An

accurate assessment of the impacts is important, and the proponent should prepare an

assessment containing at least the information outlined in this section.

Understanding the characteristics of the fisheries resource (Appendix II) is an important step in

determining what impact a proposed land development project will have on the spawning and

rearing capabilities of the streams and watercourses in the immediate or downstream vicinity.

The determination of the impacts, both positive and negative, can be assisted by assessment of

the natural conditions of the proposed development site prior to commencement of any design or

construction work. While it is not mandatory to provide an environmental impact statement to the

approving authorities, such a statement can be required at the discretion of the Minister of

Fisheries and Oceans (Fisheries Act, Section 37(1)). In areas of extremely sensitive fisheries

habitat values, land development may not be possible if DFO's policy of no net loss of the

productive capacity of those habitats is to be satisfied.

The above considerations should be adopted by regional and municipal governments as they

determine their own land use policies. Increased environmental awareness by all people

regarding the use of the finite land and water resources makes protection of fish and fish habitat

a paramount issue. If sustainable development is achieved, people will continue to enjoy all the

values associated with productive aquatic habitat and the fisheries resource in and around

developed urbanized areas.


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Application of Land Development GuidelinesThese land development guidelines should be applied to all new developments and expansions

or re-developments of existing areas. Land developments that do not have fish habitat onsite nor

any potential impact, through construction activities, land use or stormwater discharges, on fish

habitat off site or downstream are screened out of the guidelines. Generally, small land

development parcels, such as building lots, with no onsite fish habitat, but whose development

activities and runoff ultimately impact fish habitat, will require a summary document outlining

practical implementation of the guidelines and site plan similar to Figure 3.6. Areas greater than

2.0 hectares or having watercourses containing fish habitat will require a full impact assessment

document and both predevelopment site features and land development guideline implementation

plans. The screening flow chart in Figure 7.1 should be used to determine the appropriate

sections of the Land Development Guidelines that are applicable to the development.

Preparation of the document and implementation of the guidelines can be completed in four

steps.

• Collect initial predevelopment data for assessment.

• Analyze site data with implementation of land development guidelines objectives.

• Prepare site map(s) with key information.

• Prepare written impact assessment/feature document and specifications.

Collecting Predevelopment DataThe predevelopment information should be collected onsite through site inspections. A record of

site conditions should be kept with photographs and diary. An aerial photograph of the site is

useful in gaining an overall perspective. A written record or inventory of the items described

should also be completed. Projects can be initially evaluated by a layperson. For projects that

must implement sections of the guidelines (i.e. in one form or another they have the potential to

impact fish habitat and are screened into the referral process), it may be prudent to enlist the

services of a qualified environmental consultant to assist in preparing an assessment and to

advise on the precautionary or mitigative steps necessary to preserve fish and fish habitat.

Generally, information should be collected and analyzed by a person qualified or knowledgeable

in the areas investigated and could include: biologists, civil engineers, botanists, geotechnical

engineers, arborists, hydrologists, surveyors, etc. The predevelopment information should be

catalogued and displayed on the predevelopment map.


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Figure 7.1 Land Development Guidelines Screening and Application Chart


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Location and Topography

An accurate topographic map should form the basis of any kind of land development plan. The

site map should be accurate and of the appropriate size and scale to show all of the required

features. Predevelopment data and land development features will be overlaid onto the base

map to provide a visual development plan. Topographical maps can be obtained from

government sources or derived from site surveys. For a single lot development, an accurate

hand-drawn sketch illustrating the relevant features will be sufficient.

Watercourses, Drainage and Aquatic Habitat

Overland runoff and channel flow elements should be marked on the base map and detailed in

the written plan. Existing streams and channels should be detailed, as well as watershed areas

and drainage areas for intermittent and permanent waterways and for calculation of contributory

areas for sediment and detention designs. Streams, channels , ponds and wet lands should be

classified for their aquatic habitat values, sensitivities and utilization by fish. Information on the

distribution of salmonids and other freshwater fish can be obtained from the Federal/Provincial

Stream Summary Catalogues available at local DFO and MOELP offices. Initial determination of

utilization and sensitivity of aquatic habitat can be evaluated by a qualified biologist or through

consultation with DFO/MOELP habitat staff through the regional offices.

Climatic Information

Rainfall data is utilized to design erosion control, sediment control ponds and detention features.

In most instances, IDF (intensity-duration-frequency) curves for precipitation at the development

location can be used. Municipalities and Regional Governments often provide standard design

storm events or design IDF curves. The Department of Environment - Atmospheric Environment

Service has IDF data and curves for 98 stations across BC and an atlas to interpret areas

between stations.

Soils and Vegetation

Information collected should include soil types, ground cover and vegetation. Soils data should

outline areas of highly erodible materials and analysis for use in the design of sediment control

facilities and erosion control strategies. Unstable slopes and remedial measures should be

analyzed, designed and detailed using geotechnical engineering services. Existing ground cover

and vegetation such as trees and shrubs should be detailed and used in determining runoff

factors. Trees and other forms of vegetation are important aesthetic and environmental factors

as well as an effective form of erosion control. Preservation of undisturbed ground cover, trees

and shrubs within the leave strips bordering streams is essential for maintaining the integrity of

the FSZ.


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Current and Future Land Use

A description of the current and future land use of both the site and adjacent areas should be

included. Offsite features should also include streams and drainage, current and potential future

land use and encroachments. The evaluation should identify and address the following details.

• The legal description, registered ownership, options and covenants on the land involved.

• Official community plan (OCP) designation for present and future land use of the site.

• Required OCP changes for proposed development.

• Required rezoning for proposed development, date of application, and application

number.

• Total size of project in hectares.

• Designation of water supply, drainage and sewerage systems to be onsite or provided by

municipal or offsite hook-ups.

• Siting locations for storm water detention and sediment control facilities on the site.

• Siting and location of utility and access encroachments.

• Potential soils contamination if the project site was previously used for commercial or

industrial purposes (Contact MOELP Waste Management Branch for direction regarding

investigation and disposal of contaminated soil).

• Visible signs of pollution in or along the watercourses on or adjacent to the proposed site.

(If pollution is visible, please contact MOELP, DOE or DFO immediately).

Assessment and ImplementationThis procedure involves the analysis of the predevelopment information and preparation of the

land development impact assessment. This procedure may involve application of one or more

sections of the guidelines, which may include:

• Provision and Protection of Leave Strips

• Erosion and Sediment Control

• Stormwater Management

• Instream Work Guidelines

• Fish Passage and Culvert Requirements

Once the sections of the Land Development Guidelines have been applied and analysis is

complete, the following information should be transferred onto an Implementation Map.

• developed and undeveloped terrain, pervious and impervious surfaces

• building sites, roadways, utility corridors and other land use

• retained vegetation and leave strips (showing method of distinguishing clearing limits)

• altered drainage and slopes (showing runoff factors and areas used for calculations)

• instream work areas and fish passage features (if required)


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• erosion and sediment control features, location, sizes and capacities

• stormwater management facilities, location, size and capacities.

The document that accompanies the predevelopment and implementation maps is an impact

assessment document. It describes in written form the predevelopment data, and analysis and

implementation of the guidelines. It also details the following:

• The various development activities that affect the site and sensitive areas (for aquatic

habitat) on the site.

• A schedule of the activities involved with the development of the site, including

assessment, permitting, development and construction activities.

• A list and location of all guidelines features and provisions including erosion and

sediment control plans, stormwater management plans, instream work windows, etc.,

cross-referenced to the construction/activity schedule as per date and order of

installation or construction.

• A maintenance program and schedule for the various features including detailing who is

responsible for what features and conditions of maintenance.

• A contact list of the various parties involved including the owner, developer, companies

involved, prime contractor, subcontractors, consultants, etc, if known.

• The design and calculations used for the engineering and design of the erosion and

sediment control structures, stormwater management features and pollution control

works.

• Specifications that will be supplied to the contractor for the design, construction and

maintenance of the various Land Development Guideline features

If prepared as described above, the impact assessment will now contain the information generally

required to substantiate the operational implementation of the Land Development Guidelines for

DFO and MOELP fisheries habitat impact assessment purposes. They should be included as

part of the overall development plan and attached to the development/construction specifications

for bidding and contract purposes. The completed plan should be distributed to the various

parties involved in the development process (contact list) including the field construction

supervisors and workers. Use and practical implementation of the guidelines will require onsite

supervision and revision to meet the changing, site-specific conditions encountered.

Environmental MonitoringIn accordance with current practice, and where considered appropriate by government agencies,

the proponent should employ environmental monitors to ensure a high standard of environmental

protection during construction. Construction can be either continuously monitored or periodically

inspected, depending on site sensitivity and the nature of construction. The monitor should have


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the authority to modify or stop operations in the case of non-compliance with approval conditions

or where unforeseen circumstances cause environmental problems. The monitor also provides

the following services as required:

• Acting as an intermediary between the proponent and regulatory bodies.

• Briefing the contractor on site-specific environmental requirements.

• provides basic environmental education and construction guidelines to all field personnel.

• closely supervises construction activity to ensure compliance with construction

guidelines.

• Participating in meetings between proponent, agency personnel and the contractor(s).

• Defining environmental standards for construction.

• Mapping and marking sensitive areas in advance of actual construction.

• Reporting to the proponent and the regulatory agencies on the environmental

performance of the contractor.

The proponent, by allowing the monitor to represent agency concerns, benefits since this allows

the proponent to avoid shutdowns and other costly complications that would otherwise result from

preventable environmental violations. Regulatory agency personnel may overrule the

environmental monitor, and have final authority in determining whether or not construction

standards are being met by the contractor.


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SECTION 8LAND DEVELOPMENT EXAMPLE

ObjectiveThis design example illustrates the application of the Land Development Guidelines to a small

development site. In the application of the erosion and sediment control guidelines, an

interceptor ditch/swale and sediment control pond are designed. Also, this design example

utilizes the rational method, simplified unit hydrograph and alternate infiltration system in the

design of the stormwater management requirements. Where possible, information is included to

provide additional background and detail to the methods used. The methodologies used are

examples and illustrations, not endorsements or minimum requirements, for calculating

requirements outlined in the Land Development Guidelines.

Predevelopment Data (see Figure 8.1 Predevelopment Map )Location and Topography

The development site is located near Campbell River at Willow Point, west of the main highway

on Vancouver Island. The site slopes generally to the west, with a small section near the

highway draining to the east. The change in elevation onsite is from 60.5 m. to 52 m. (above

datum).

Drainage

Current runoff is by overland flow following the slope of the site. A small gully is located off the

property near the SW corner which appears to have concentrated channel flow during runoff

events. The small section at the east end of the site currently drains onto the road r/w. There is

no generation of runoff onto the development area from offsite precipitation.

Soils and Vegetation

The site is overlain with a sandy organic topsoil in the open areas, and a darker organic humus

with leaf litter under the alder canopy. Test pits were dug at locations indicated and soil logs are

included. The south third of the property has a mature alder forest 8 to 12 meters high with a

fern/salal/grass ground cover. The other two thirds of the property is vegetated with open

grasses, broom and small alder.

Streams and Aquatic Habitat

There are no permanent or intermittent streams or watercourses onsite. There is a large stream,

Willow Creek, offsite near the west end of the property which, according to the Stream Summary

Catalogue, is utilized by salmonids (copy of catalogue data is enclosed).


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Figure 8.1 Predevelopment Map


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Description

Stream Name: Willow Creek

Local Name: Swansky/Ford Creek

Watershed Code: 92-2645

Location: Flows NE into Discovery Passage at Willow Point, SE of Campbell River.

Distribution Summary

CO Coho Salmon Throughout (above site).

CM Chum Salmon Presence Noted (above site).

CT Cutthroat Trout Presence Noted (above site).

FSZ Area: Area 1

FSZ Window: Aug 1 - Sep 15 (Final window to be determined with DFO/MOELP consultation)

Climatic Information

IDF curves for development site were derived from Environment Canada - Atmospheric

Environment Service Rainfall Frequency Atlas for Canada (1985) using estimates of mean

rainfall, standard deviation and frequency factors from rainfall frequency maps.

Current/Future Land Use

The current zoning and OCP designation allows for development of a light commercial/business

center. The total site area is 2.2 hectares. Water supply and sewerage are provided along the

frontage with the r/w together with site access and utilities hook-ups. Site stormwater

management is to be provided onsite with discharge to creek after treatment/detention.

Development/Construction Schedule

Table 8.1 - Example Development Construction Schedule

Construction/Development Activity Start Date Finish Date Responsibility

Site access construction May 5 May 8 Contractor

Clearing, earthworks and grading May 9 May 15 Contractor

Erosion and sediment control features May 13 May 20 Contractor

Site services/foundations May 21 June 10 Contractor

Building construction June 10 July 31 Contractor

Stormwater facilities Aug 1 Aug 7 Contractor

Stormwater outfall (FSZ) Aug 8 Aug 14 Contractor

Paving/landscaping Aug 15 Aug 30 Contractor


91

Controlled Activities/Construction ZonesThere will be no work or disturbance with thirty (30) meters of the existing high water mark of

Willow Creek along the entire western boundary of the development site. This area will be

maintained as a leave strip and protected by orange construction fence during development and

removed after final DFO inspection. There is no instream work planned for the development of

this site. Existing runoff gully is to be widened and armoured during FSZ window to be confirmed

and approved with DFO Fisheries Officer and MOELP. Controlled construction techniques

include the use of hand labour and no machinery. The gully is being widened and armoured to

prevent erosion due to stormwater flows from the detention pond.

LDG Features and Construction ScheduleLeave Strip

• Provision and protection of a minimum 30 meters from existing high water mark of Willow

Creek.

• Installation of landscaped area next to leave strip as buffer area to developed site.

• Barrier fencing will be placed at initial site meeting and removed after final DFO

inspection.

Erosion and Sediment Control and Construction Practices

(see Figure 8.2 Erosion and Sediment Control Map)

• Temporary re-vegetation of developed area between initial site earthworks and

construction.

• Installation of lined interceptor ditch around disturbed area to control runoff.

• Tarping of exposed fill slopes until permanent vegetation is established to minimize

erosion.

• Limit construction access and install working road to minimize soil disturbance.

• Removal of excess fill materials offsite.

• Installation of sediment control pond.

• Improvement of existing offsite gully to prevent erosion due to concentrated runoff flows.

• Installation of permanent landscaping at earliest possible date after construction.

• Onsite control of waste materials and installation of recycling/waste control area for

contractors/subcontractors.

• Enforcement of good housekeeping, Worker's Compensation Board, and relevant codes

and by-laws, for site services and conditions.


92

Figure 8.2 Erosion and Sediment Control Map


93

Stormwater Management (see Figure 8.3 Developed Site Map)

• Installation of a wet detention pond to control runoff rates to 1:2 storm event

predevelopment conditions.

• Detention facilities to be operational before completion of storm drainage system and site

paving.

• Installation of spill-control type inlet and outlet structures and oil absorbent pads in wet

pond.

Maintenance ScheduleContractor shall be responsible for maintenance of the features as listed below and on the site

drawings during construction. Owner assumes responsibility of all features upon final inspection.

Maintenance items include:

• Erosion control tarping and re-vegetation.

• Interceptor ditch.

• Sediment control pond.

• Wet detention pond.

• Site waste and access control.

Contact List• Registered Owner

• Prime Contractor

• Land Development Consultant


94

Figure 8.3 Developed Site Map


95

Figure 8.4 Stream Information Summary (SIS) Report Datafor Land Development Example


96


97

Calculation of Runoff Flows in Land Development Guidelines ExampleTo determine flows in the design example, it is assumed that runoff flows via two modes. The

first is overland in the form of sheet and shallow channel flow. Flow of this nature can be

calculated using time of concentration, IDF precipitation data and the rational formula. The

second mode of runoff type is open channel flow where Manning's equation can be used, or

Bernoulli's equation can be used for pressurized flow in a pipe. In this design example, the

rational method is used to determine overland flows used to size the erosion and sediment

control features, and the stormwater detention facilities. Suitable factors of safety should be

added to features calculated in terms of capacity of flow and volume to ensure protection of the

structures, the public, and the environment (e.g. freeboard on ponds and channels, emergency

spillways, etc). The use of the rational formula and time of concentration methodology has

limitations, and should be considered the minimum required standard for computation of

stormwater runoff flows. In large land developments with complex drainage systems, it is

prudent to use a more involved computational method, like the SCS (U.S. Soil Conservation

Service) unit hydrograph method or continuous simulation hydrograph-based methods, to

compute stormwater flows and detention requirements.

Rational Formula

The rational formula used in this design example takes the form:

=

where Q equals runoff flow (m 3/s), R (or C) is the runoff factor, A is the catchment area (ha) and

I equals the precipitation intensity (mm/hr). The maximum catchment area suitable for

application of the rational formula is 10 hectares. In the selection of R or C factors for the rational

formula and overland flow characteristics, care and thought should be used in regard to type,

function and lifetime of the structure being designed. In this example, the table of runoff

coefficients used was as follows:

Table 8.2 - Land Cover Factors used for Rational Formula

Land Cover Type R Land Cover Type R

Dense Forest 0.05 - 0.15 Unpacked/Rough Soils 0.30 - 0.50

Light Forest 0.15 - 0.25 Graded/Smooth Soils 0.40 - 0.60

Range/Pasture 0.20 - 0.30 Impervious Surfaces 0.80 - 0.95

Lawn/Grassed Areas 0.15 - 0.35 Open water 1.0

Fisheries and Oceans


RIA


360




Q




98

These ranges of values illustrate the variability in runoff factors and the caution required when

selecting the value for the land form type. Higher values in the range generally correspond to

steeper sloped sites, frozen conditions, or relative poor underlying soil permeability or drainage.

Time of Concentration - Tc

Time of concentration (Tc) is the estimate of the time required for runoff to contribute from the

total area, and is equal to the time of runoff travel from the farthest point in the catchment area to

the point under consideration. Theoretically, a storm event with a duration equal to Tc will

develop the peak runoff rates equal to the intensity of precipitation of that duration over that

catchment area. Generally, storm events of longer duration (larger Tc) will have lower

precipitation intensities and peak runoff rates, but often similar total volume of runoff, in

comparison to shorter, more intense storms. For application to the rational formula, the minimum

catchment Tc is 5 minutes and the maximum catchment Tc is 100 minutes. The minimum Tc

ensures that runoff is generated from smaller, less pervious areas, and the maximum Tc limits

the size of the catchment area and length of flow path. One example of calculating time of

concentration values is by using a nomograph based on slope and rational formula runoff

coefficients (example of Tc nomograph, pg. 4.20, Goldman et al.). A second method uses a

basic formula based generally on Manning's equation and adapted to overland flow conditions.

The formula method adapted for use in the Land Development Guidelines design example was

derived from the Draft Stormwater Management Manual for the Puget Sound Basin. The

formula calculates the Tc (minutes) for overland flow conditions and is intended for use with use

with the Rational formula:

where L is the flow path length (m), s is the slope (m/m), and K is the land cover factor.

Table 8.3 - Land Cover Factors used in Overland Flow Tc Calculation

Land Cover Type K Land Cover Type K

Forest 0.76 Unpacked/Rough Soils 3.1

Range/Pasture 1.4 Packed/Smooth Soils 4.6

Lawn/Grassed Areas 2.1 Impervious Surfaces 6.1

Note that for open water, the time of concentration is assumed equal to zero. Density of

vegetation and presence of channelization will result in variations to these average K values.


Tc=


60K


s


L


99

Recurrence Intervals

The recurrence interval is used to determine the design storm event for interceptor ditches,

sediment control ponds and detention structures. The recurrence interval or return period is the

number of years between events (e.g. floods, precipitation, snowfall) of a certain duration and

intensity. In the design of hydraulic structures, engineering-economic analysis provides the basis

for the design of a structure's capacity to be periodically exceeded rather than having to build a

larger, more costly structure whose capacity would never be reached. In the design of temporary

facilities, a lower recurrence interval is used, accepting a higher risk of failure because of the

relatively short time the facility is operational. For permanent facilities, and those whose failure

would result in direct impacts to property and people, a higher recurrence interval with lower

associated risk is used. In the design of detention facilities, the lower recurrence interval

(predevelopment 1:2 year) was selected to prevent environmental damage resulting from floods

greater than the mean annual (occurring approximately every 1:2 years) generated from

developed areas in a watershed. The emergency spillway capacities of pond structures, whose

structural failure would have a great impact downstream on property, people and the

environment, are designed for a 1:100 year event. Below is a summary of the design

requirements for the Land Development Guidelines according to recurrence interval and area.

Table 8.4 - Recurrence Intervals and Catchment Areas

Structure Recurrence Interval Area

IC Ditch 1:2 Catchment

Sediment Pond Area 1:2 Catchment

Sediment Pond Outlet/Spillway 1:100 Catchment

Detention Pond Volume 1:2 Pre and Post-development

Detention Pond Outlet/Spillway 1:100 Post-development

Additional factors of safety, including: provision of freeboard around ponds and channels,

additional storage in detention structures, increased settling area for sediment control ponds and

reduced design infiltration rates for infiltration systems, are used to ensure safe and long-term

operation.


100

Calculations for Land Development Guidelines ExampleCalculations for the design example include:

• Calculation of design storm events from IDF data derived from AES rainfall charts.

• Design of interceptor ditch for erosion and sediment control.

• Design of sediment control pond for erosion and sediment control.

• Calculation of design flows for predevelopment conditions, developed conditions and

detention requirements using rational method and IDF data.

• Design of wet detention pond for detention requirements.

• Design of alternate infiltration system for detention requirements.

Intensity-Duration-Frequency Data for Development Site

For the location of the site, values of the mean and standard deviation for annual extremes of

rainfall (mm/hour) were extracted from the AES Rainfall Frequency Atlas for Canada. Distance

between isolines was estimated and values for the various durations were recorded. Using the

appropriate frequency factors for the frequency or recurrence intervals, intensities in mm/hour for

the various durations were calculated. Note that according to Table 1, pg. 9 of the atlas, an

augmentation factor for orographic precipitation is applied for storms of certain durations (i.e.

mountainous regions have an multiplication factor applied to precipitation values). Simple linear

regression of a log-log plot of IDF data produces a graph. The graph can be used to calculate

precipitation intensities for storms of a certain duration and frequency. For example, a 2 year

(1:2) storm with a 20 minute duration has an intensity of 20 mm/hour.

Table 8.5 - Land Development Example IDF Data

PrecipitationDuration

(min)

MeanPrecipitation

(mm)

Std. Deviation ofPrecipitation

(mm)

5 2.9 1.5

10 4.5 1.7

15 5.5 1.9

30 7.5 3

60 12 5

120 17 4

360 32 8

720 45 8

1440 55 15


101

Figure 8.5 Land Development Example Site IDF Curves

Design of Interceptor Ditch

The interceptor ditch is designed for the runoff resulting from a 2 year (1:2) storm event. From

the erosion and sediment control map, the data required to determine the runoff is:

• Area 1.628 hectares

• Runoff Factor (R or C) 0.4

• Overland flow path 155 meters

• Recurrence Interval 2 years (1:2)

• Area slope 0.5%

• Land Cover Factor (K) 2.5.

Using the formula, a time of concentration value of approximately 15 minutes was derived. From

our site IDF curves, this results in a precipitation event of 23 mm/hour. Using the rational

formula, the total peak overland flow that must be carried is calculated to be 0.042 m3/s or 1.5

cfs. Using Manning's formula for open channel flow and the worst case conditions, we can

calculate the depth of water resulting from the overland flow and design our interceptor ditch

according to the guideline parameters. In this case, we have chosen to line the ditch with

polyethylene.

The worst slope (i.e. flattest) is along the back of the site estimated at 1%. Assuming a v-notch

(90°) channel is constructed, Manning's n=0.013 for the lining, a slope = 0.01, and channel length

= 100 meters and:


1000


100


10


1


1


10


100


1000


10000


DURATION (minutes)


INTENSITY (mm/hr)


2


5


10


100


102

= and = and =

then:

= =

Therefore the lined ditch should be 0.18 meters deep + freeboard of 0.30 meters = 0.48 meters in

depth and the resulting velocity would be:

= = =

Based on the resulting velocity and length of ditch we can estimate channel travel time to check

that the initial estimate for time of concentration is accurate. Therefore:

Time of Concentration = Overland Flow Time + Channel Flow Time

= + = + = + =

Re-checking the flows, the 1:2 precipitation intensity for Tc equal to 16.3 minutes is

approximately equal to the intensity for 15 minutes, and our initial flow estimate is correct.

Design of Sediment Control Pond

In this design, the resulting pond design peak inflow is 0.042 m 3/s based on a recurrence interval

of 2 years. According to the guidelines area requirement for settling ponds:

AQ

Vs= 1 2.

= 250 m2

Using the factor for effective length-to-width ratio of 5:1 and 5 w 2 = 250 m 2, the resulting effective

width should be equal to 7.1 meters and the effective length equal to 35.5 meters. Checking the

required area for minimum hydraulic detention time of 40 minutes:

= =

Area required for particle settling governs and the average effective pond area at design flows

should be equal to 250 m 2.


Q


n


AR


S


R


d


A=d


2


2


2


2


1


3


2


Q=0.042 m


3


s


AR









A


2400Q


0.5 depth


201.6 m


2


Tc


Initial Tc


L


60V


15


100


60 x 1.24


15


1.3


16.3 minutes


V


R


S


d


S


2



1


3



2


2


1


3


2


n


2n


1.24 m/s


2


3


1


2


S


n


2n


d


S


8


3


1


2


103

To design the correct orifice area requirement for the sediment pond drawdown ports:

=

where T equals drawdown time required (48 hours), orifice coefficient of discharge (Cd) equal

0.6, A equals average pond area (250 m2), and h equals pond depth (0.5 meters). Substituting

values into the equation yields a drawdown port area of 770 mm2 or hole diameter equal to 31

mm. The riser is designed for the 1:100 year runoff, which results in a precipitation intensity of

57 mm/hour and a design peak flow of 0.10 m3/s. By using the sharp-crested weir equation the

design water elevation above the riser stack can be determined. Assuming a 450 mm diameter

riser pipe, C (weir coefficient) is set at 3.4 and L is equal to πd, the head above the riser crest

can be calculated:

HQ

Cd=

π

23

The resulting head above the riser pipe at 1:100 year runoff rates is 0.08 meters. The

emergency spillway is also designed for a 1:100 event, in case the riser outflow is blocked. The

last design check is to ensure the mean horizontal pond velocity is below the critical suspension

velocity of the design particle. The horizontal velocity is equal to:

Vh = Qwd = 0.025 m/s < 0.075 m/s = design particle critical scour velocity.

The pond design guidelines will determine final physical sediment pond lay-out and size. The

riser design details, maintenance requirements and interval, and location should be detailed on

pond plan.

Calculation of Detention Requirements

The objective of the Land Development Guidelines is to limit the peak post-development runoff to

the 1:2 predevelopment levels. First, the predevelopment 1:2 peak runoff rate must be

determined using, in this case, the rational formula and an analysis of the land cover type, area

and slopes. By following the contours, the general overland flow is across the site, with no

discrete channel flow elements. The area-weighted runoff factors and times of concentration,

using the Tc formula, were calculated on a spreadsheet (Figure 8.6). The 1:2 peak

predevelopment flow, derived with IDF data and the rational method, was calculated to be 0.022

m3/s. Next the post development conditions were analyzed, and a peak post-development

discharge of 0.097 m3/s was obtained. In order to calculate the detention requirements, a

simplified hydrograph for the site was developed. Time dependent rates of runoff were

calculated using the rational formula and IDF data. It was assumed that the predevelopment rate

of runoff continues at peak rates for storms of duration greater than Tc predevelopment. Post-

development runoff rates decreased as intensities decreased with greater duration (time).


A


2h


Cd3600T



g


104

Figure 8.6 Calculation of Predevelopment and Post-development Peak Flowsfor Land Development Example

Predevelopment Condition

Overland FlowSub-basinNumber

Sub-basin LandCoverType

Sub-basin Area(ha)

RunoffFactor

R

OverlandFlow Path(meters)

Land CoverFactor

(K)

Slope Tc(min)

1 forest 1.229 0.25 119 0.75 0.03 15

2 forest 0.6471 0.15 71 0.75 0.07 6

TOTAL 1.8761 0.22 21

Peak Flow (m3/s) 0.022

Post-development Condition

Overland FlowSub-basinNumber

Sub-basin LandCoverType

Sub-basin Area(ha)

RunoffFactor

R

OverlandFlow Path(meters)

Land CoverFactor

(K)

Slope Tc(min)

1 roof/pavement 1.271 0.90 155 5 0.01 5

2 tree/grass 0.71 0.15 75 0.8 0.11 5

Channel FlowFrom - ToSub-basin

CalculatedSub-basin Flow

(m3/s)

Manning'sn

Slope PipeDia(m)

Area(m2)

Depth

(m)

Velocity(m/s)

FlowPath(m)

Tc

(min)

1 - 2 0.126 0.020 0.050 0.6 0.09 0.22 2.75 75 0.45

TOTAL 1.981 0.63 10

Peak Flow (m3/s) 0.097

The difference between the predevelopment and the post-development rates of runoff is the

stormwater runoff that must be detained in order to meet the objectives of the guidelines. This

detention volume was calculated by multiplying the difference between the two runoff rates with

elapsed time, and the resulting cumulative volume was calculated in the spreadsheet (see Figure

8.7). The difference in the predevelopment and post-development rates of runoff is visually

represented by the two simplified hydrographs. For the design example, the required detention

volume was calculated to be 194.2 cubic meters.


105

Figure 8.7 Calculation Spreadsheet and Simplified Hydrograph for DetentionVolume Requirements

Time(minutes)

PredevelopmentFlows(m3/s)

Post-developmentFlows(m3/s)

PreDVolume

(m3)

PostDVolume

(m3)

Volume toDetention

(m3)

CumulativeVolume

(m3)

0 0.000 0.000 0.0 0.0 0.0 0.0

10 0.011 0.097 3.3 30.1 26.8 26.8

21 0.022 0.068 10.6 53.8 43.2 70.0

30 0.022 0.057 11.5 32.7 21.2 91.2

60 0.022 0.040 39.3 87.1 47.8 139.0

90 0.022 0.033 39.3 65.4 26.1 165.1

120 0.022 0.028 39.3 54.8 15.5 180.6

150 0.022 0.025 39.3 48.1 8.8 189.4

180 0.022 0.023 39.3 43.4 4.1 193.5

200 0.022 0.022 25.9 26.6 0.7 194.2

DetentionVolume

194.2 m3


0.1


0.09


0.08


0.07


0.06


0.05


0.04


0.03


0.02


0.01


0


0


20


40


60


80


100


120


140


160


180


200


pre Tc= 21 min



Predevelopment Flows


Postdevelopment Flows


post Tc = 10 min


TIME


F


L


O


W


106

Design of a Wet Detention Pond

When calculating the required detention volume, an additional volume is added for a factor of

safety to account for increased runoff or future development. In the design example, the

calculated detention volume is multiplied by 1.5 to achieve a design volume of ≈ 300 m3. For a

dry detention pond, the average pond area would be approximately 300 m2 based on a maximum

pond depth of 1.0 meters. The physical size and dimensions of the dry pond structure would be

determined by the guideline parameters. For a wet detention pond, the average pond area

would depend on the maximum active detention zone depth. Assuming an active detention zone

depth of 1.0 meters, a design detention volume: V, a bench slope of 1:7, and a permanent pool

effective length equal to 5 x effective width, the average area (A) required is equal to:

AV

d= = = =

300

1 0300

.

(W x 5W) + [(W + 7) x (5W + 7)]

2

The resulting quadratic equation is:

10 42 551 02W W+ − =

By solution, the dimensions of the wet pond are:

• Permanent pool 5.6 m. x 28.0 m.

• Design full pool 12.6 m. x 35.0 m.

• Permanent pool depth should vary from 0 to 1.2 m.

• Detention storage depth 1.0 m.

Based on a design riser height (h) of 1.0 meters over the orifice and the orifice equation, the port

area required to limit the pond flow to the peak predevelopment level at full riser depth is:

Aport m( )2 = =preQ

Cd 2gh

0.0 22

0.6 2 x 9.8 1 x 1.0 = 0.0083 m2 = 103 mm diameter orifice

The time to drain the detention volume can be calculated:

T 300 2 x 1.00.6 x 3600 x 0.0083 9.81

= = 7.56 hours

The riser is designed for the 1:100 year runoff, which results in a precipitation intensity of 70

mm/hour and a design peak flow of 0.244 m3/s. By using the sharp-crested weir equation the

design water elevation above the riser stack can be determined. Assuming a 450 mm diameter

riser pipe, C (weir coefficient) is set at 3.4 and L is equal to πd, the head above the riser crest

can be calculated:

HQ

Cd=

π

23


107

The resulting head above the riser crest is equal to 0.15 meters. The emergency spillway is also

designed for a 1:100 event, in case the riser outflow is blocked.

Design of Alternate Infiltration System

Using the design detention volume of 300 m3, a field saturated percolation rate (at the infiltrating

surface at depth) of 20 cm/hour, and a void ratio of infiltrating media of 0.4, the calculated

required volume of media to retain 1:2 year detention volume.

Volume Infiltration Gallery (LxWxD) = Detention VolumeDesign Void Ratio

3000.4

= = 750 m3

Minimum Infiltration Area (LxW) = = 2 30048 0.2

×× = 62.5 m2

Calculate Minimum Dimensions for suitable Infiltration Gallery:

• D 3.5 meters

• L = W 15.0 meters.

As the design area is approximately 3.5 times that required, the gallery will dewater sufficiently

between storms. The low hydraulic loading rate will also prolong the effective lifetime of the

infiltration gallery. Ensure drainage from the site in frozen or oversaturated conditions with the

provision of a channel or pipe. Location, dimensions and site conditions should meet guidelines

recommendations. Inflows should be treated in a small settling basin or sump to remove

sediments that could clog exfiltrating soils and reduce void volume of infiltrating media.


2 x Detention Volume


48 x Perc. Rate


108

APPENDIX IREGULATIONS

Habitat-Related Sections of the Fisheries Act (Canada)The sections of the Fisheries Act (R.S.C., 1985, c. F-14; as amended by Statutes of Canada

1988, c. 49) which are pertinent to land development purposes are provided herein for reference

and it is recommended that the reader refer to a copy of the Act for further details and

understanding.

Section 22(2): Protection of fish passage during construction.

The owner or occupier of any obstruction shall make such provision as the Minister determines to

be necessary for the free passage of both ascending and descending migratory fish during the

period of construction thereof.

Section 26(1): Main channel not to be obstructed.

One-third of the width of any river or stream and not less than two-thirds of the width of the main

channel at low tide in every tidal stream shall be always left open, and no kind of net or other

fishing apparatus, logs or any material of any kind shall be used or placed therein.

Section 28: Use of explosives prohibited.

No one shall hunt or kill fish or marine mammals of any kind, other than porpoises, whales,

walruses, sealions and hair seals, by means of rockets, explosive materials, explosive projectiles

or shells.

Section 32: Destruction of fish.

No person shall destroy fish by any means other than fishing except as authorized by the Minister

or under regulations made by the Governor in Council under this Act.

Section 34(1): Definitions.

For the purposes of sections 35 to 43, "deleterious substance" means

(a) any substance that, if added to any water, would degrade or alter or form part of a

process of degradation or alteration of the quality of that water so that it is rendered or is

likely to be rendered deleterious to fish or fish habitat or to the use by man of fish that

frequent that water, or

(b) any water that contains a substance in such quantity or concentration, or that has been

so treated, processed or changed, by heat or other means, from a natural state that it

would, if added to any other water, degrade or alter or form part of a process of

degradation or alteration of the quality of that water so that it is rendered or is likely to be

rendered deleterious to fish or fish habitat or to the use by man of fish that frequent that

water,


109

and without limiting the generality of the foregoing includes

(c) any substance or class of substances prescribed pursuant to paragraph (2)(a),

(d) any water that contains any substance or class of substances in a quantity or

concentration that is equal to or in excess of a quantity or concentration prescribed in

respect of that substance or class of substances pursuant to paragraph (2)(b), and

(e) any water that has been subjected to a treatment, process or change prescribed

pursuant to paragraph (2)(c);

"deposit" means any discharging, spraying, releasing, spilling, leaking, seeping, pouring, emitting,

emptying, throwing, dumping or placing;

"fish habitat" means spawning grounds and nursery, rearing, food supply and migration areas on

which fish depend directly or indirectly in order to carry out their life processes;

Section 35(1): Harmful alteration, etc., of fish habitat prohibited.

No person shall carry on any work or undertaking that results in the harmful alteration, disruption

or destruction of fish habitat. (See s. 40(1) for "Offence & Punishment" section)

Section 35(2): Alteration, etc., of fish habitat authorized.

No person contravenes subsection (1) by causing the alteration, disruption or destruction of fish

habitat by any means or under any conditions authorized by the Minister or under regulations

made by the Governor in Council under this Act.

Section 36(3): Deposit of deleterious substance prohibited.

Subject to subsection (4), no person shall deposit or permit the deposit of a deleterious

substance of any type in water frequented by fish or in any place under any conditions where the

deleterious substance or any other deleterious substance that results from the deposit of the

deleterious substance may enter any such water. (See s. 40(2) for "Offence & Punishment"

section)

Section 37(1): Minister may require plans and specifications.

Where a person carries on or proposes to carry on any work or undertaking that results or is

likely to result in the alteration, disruption or destruction of fish habitat, or in the deposit of a

deleterious substance in water frequented by fish or in any place under any conditions where that

deleterious substance or any other deleterious substance that results from the deposit of that

deleterious substance may enter any such waters, the person shall, on the request of the

Minister or without request in the manner and circumstances prescribed by regulations made

under paragraph (3)(a), provide the Minister with such plans, specifications, studies, procedures,

schedules, analyses, samples or other information relating to the work or undertaking and with

such analyses, samples, evaluations, studies or other information relating to the water, place or

fish habitat that is or is likely to be affected by the work or undertaking as will enable the Minister

to determine


110

(a) whether the work or undertaking results or is likely to result in any alteration, disruption or

destruction of fish habitat that constitutes or would constitute an offence under

subsection 40(1) and what measures, if any, would prevent that result or mitigate the

effects thereof; or

(b) whether there is or is likely to be a deposit of a deleterious substance by reason of the

work or undertaking that constitutes or would constitute an offence under subsection

40(2) and what measures, if any, would prevent that deposit or mitigate the effects

thereof.

Section 37(2): Powers of Minister.

If, after reviewing any material or information provided under subsection (1) and affording the

persons who provided it a reasonable opportunity to make representations, the Minister or a

person designated by the Minister is of the opinion that an offence under subsection 40(1) or (2)

is being or is likely to be committed, the Minister or a person designated by the Minister may, by

order, subject to regulations made pursuant to paragraph (3)(b), or, if there are no such

regulations in force, with the approval of the Governor in Council,

(a) require such modifications or additions to the work or undertaking or such modifications

to any plans, specifications, procedures or schedules relating thereto as the Minister or a

person designated by the Minister considers necessary in the circumstances, or

(b) restrict the operation of the work or undertaking,

and, with the approval of the Governor in Council in any case, direct the closing of the work or

undertaking for such period as the Minister or a person designated by the Minister considers

necessary in the circumstances.

Section 38(4): Duty to report.

Where, out of the normal course of events, there occurs a deposit of deleterious substance in a

water frequented by fish or a serious and imminent danger thereof by reason of any condition,

and where any damage or danger to fish habitat or fish or the use by man of fish results or may

reasonably be expected to result therefrom, any person who at any material time

(a) owns the deleterious substance or has the charge, management or control thereof, or

(b) causes or contributes to the causation of the deposit or danger thereof,

shall, in accordance with any regulations applicable thereto, report such occurrence to an

inspector or such other person or authority as is prescribed by the regulation.

Section 38(5): Duty to take all reasonable measures.

Every person referred to in paragraph (4)(a) or (b) shall, as soon as possible in the

circumstances, take all reasonable measures consistent with safety and the conservation of fish

and fish habitat to prevent any occurrence referred to in subsection (4) or to counteract, mitigate

or remedy any adverse effects that result or may reasonably be expected to result therefrom.


111

Section 38(6): Power to take or direct remedial measures.

Where an inspector, whether or not a report has been made under subsection (4), is satisfied on

reasonable grounds that there is an occurrence referred to in subsection (4) and that immediate

action is necessary in order to carry out ant reasonable measures referred to in subsection (5),

he may, subject to subsection (7) and the regulations, take any such measures or direct that they

may be taken by any person referred to in paragraph (4)(a) or (b).

Section 40(1): Offence and punishment (s. 35).

Every person who contravenes subsection 35(1) is guilty of

(a) an offence punishable on summary conviction and liable, for a first offence, to a fine not

exceeding three hundred thousand dollars and, for any subsequent offence, to a fine not

exceeding three hundred thousand dollars or to imprisonment for a term not exceeding

six months, or to both; or

(b) an indictable offence and liable, for a first offence, to a fine not exceeding one million

dollars and, for any subsequent offence, to a fine not exceeding one million dollars or to

imprisonment for a term not exceeding three years, or to both.

Section 40(2): Offence and punishment (s. 36).

Any person who contravenes subsection 36(1) or (3) is guilty of

(a) an offence punishable on summary conviction and liable, for a first offence, to a fine not

exceeding three hundred thousand dollars and, for any subsequent offence, to a fine not

exceeding three hundred thousand dollars or to imprisonment for a term not exceeding

six months, or to both; or

(b) an indictable offence and liable, for a first offence, to a fine not exceeding one million

dollars and, for any subsequent offence, to a fine not exceeding one million dollars or to

imprisonment for a term not exceeding three years, or to both.

Section 40(3): Other offences (s. 37 - 38).

Every person who

(a) fails to provide the Minister with any material or information requested pursuant to

subsection 37(1) within a reasonable time after the request is made,

(b) fails to provide or submit any material, information or report that is to be provided or

submitted under regulations made pursuant to subsection 37(3),

(c) fails to make a report that he is required to make under subsection 38(4),

(d) carries on any work or undertaking described in subsection 37(1)

(i) otherwise than in accordance with any material or information relating to the work

or undertaking that he provides to the Minister under subsection 37(1),

(ii) otherwise than in accordance with any such material or information as required

to be modified by any order of the Minister under paragraph 37(2)(a), or


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(iii) contrary to any order made by the Minister under subsection 37(2),

(e) fails to take any reasonable measures that he is required to take under subsection 38(5)

or fails to take such measures in the required manner,

(f) fails to comply with the whole or any part of a direction of an inspector under subsection

38(6), or

is guilty of an offence punishable on summary conviction and liable, for a first offence, to a fine

not exceeding two hundred thousand dollars and, for any subsequent offence, to a fine

not exceeding two hundred thousand dollars or to imprisonment for a term not exceeding

six months, or to both.

Section 40(5): Matters of proof.

For the purpose of any proceedings for an offence under subsection (2) or (3),

(a) a "deposit" as defined in subsection 34(1) takes place whether or not any act or omission

resulting in the deposit is intentional; and

(b) no water is "water frequented by fish" as defined in subsection 34(1), where proof is

made that at all times material to the proceedings the water is not, has not been and is

not likely to be frequented in fact by fish.

Section 78.1: Successive days separate offences.

Where any contravention of this Act or any of the regulations is committed or continued on more

than one day, it constitutes a separate offence for each day on which the contravention is

committed or continued.

Section 78.2: Offences by corporate officers, etc.

Where a corporation commits an offence under this Act, any officer, director or agent of the

corporation who directed, authorized, assented to, acquiesced in or participated in the

commission of the offence is a part to and guilty of the offence and is liable on conviction to the

punishment provided for the offence, whether or not the corporation has been prosecuted.

Section 78.3: Offence by employers.

In any prosecution for an offence under this Act, it is sufficient proof of the offence to establish

that it was committed by an employee or agent of the accused, whether or not the employee or

agent is identified or has been prosecuted for the offence, unless the accused established that

the offence was committed without the knowledge or consent of the accused.


113

Excerpts from the Water Act (British Columbia)CHAPTER 429(Consolidated February 29, 1988)

Interpretation

In this Act

"divert", or a word of similar import, means taking water from a stream, and includes causing

water to leave the channel of a stream and making a change in or about the channel that permits

water to leave it;

"engineer" means an engineer appointed under section 28 and includes the regional water

manager;

"stream" includes a natural watercourse or source of water supply, whether usually containing

water or not, ground water, and a lake, river, creek, spring, ravine, swamp and gulch;

"works" means anything capable of or useful for diverting, storing, measuring, conserving,

conveying, retarding, continuing or using water, or for producing, measuring, transmitting or using

electricity, or for collecting, conveying or disposing of sewage or garbage or for preventing or

extinguishing fire, and includes access roads to any of them, and includes the placing of booms

and piles in and the removal of obstructions from the banks and beds of streams.

Approvals by comptroller or regional water manager

7.(1) The comptroller or the regional water manager may, without issuing a licence, approve

the diversion or use, or both, of water on the conditions he considers advisable where

(a) non-recurrent use of water is required for a term not exceeding a period of 6

months;

(b) a municipality desires to exercise its powers, subject to the Water Act, under

Division (3) of Part 13 of the Municipal Act;

(c) a public corporate body or a person desires to make changes in and about a

stream;

(d) a minister of the Crown, either of Canada or the Province, desires to make

changes in and about a stream;

but the water may only be used subject to the same provisions as if the approval were a

licence.

7.(2) Notwithstanding that a licence has not been issued, a person is not prohibited from

diverting or using water in accordance with an approval given under this section.

Powers of engineer

37.(1) In addition to all other powers given under this Act and the regulations, every engineer

may

(a) enter at any time on any land;


114

(b) inspect, regulate, close or lock any works;

(c) determine what constitutes beneficial use of water;

(d) order the repair, alteration, improvement, removal of or addition to any works;

(e) order the construction, installation and maintenance of any measuring device;

(f) regulate, in person or through a water bailiff, the diversion, storage, carriage,

distribution and use of water;

(g) determine allowances of water to offset evaporation and seepage;

(h) order the release of stored or impounded water that he considers a danger to life

or property;

(i) order a person to cease putting or not to put any sawdust, timber, tailings, gravel,

refuse, carcass or other thing or substance into a stream; and

(j) order a person to remove from a stream any substance or thing that he has put

into or permitted to get into the stream.

Offences

41.(1) A person commits an offence who

(a) wilfully hinders, interrupts or causes or procures to be hindered or interrupted, a

licensee or his managers, contractors, servants, agents, workers or any of them,

in the lawful exercise of a right granted under this Act or a licence;

(b) wilfully destroys, injures or interferes with the works of a licensee without lawful

authority;

(c) opens or closes without authority a hydrant used for fire protection, or obstructs

free access to a hydrant stop cock or hydrant accessory, or damages a hydrant

stop cock or hydrant accessory;

(d) lays or causes to be laid a pipe, or constructs or causes to be constructed a ditch

or other conduit to connect with the works of a licensee without authority from the

comptroller, engineer or the licensee;

(e) molests, interferes with, delays, obstructs or otherwise impedes the comptroller

or an engineer, water bailiff or other officer in the discharge or performance of a

duty or the exercise of an authority under this Act;

(f) destroys, injures or tampers with

(i) works; or

(ii) a gauge, weir, measuring device, structure, appliance, cable, boat,

instrument or tool belonging to or placed in position by an applicant,

licensee or official of Canada or of the Province;

(g) places, maintains or makes use of an obstruction in the channel of a stream

without authority;


115

(h) engages in the business of operating works to carry water for others without

holding a licence or other authority issued in that behalf under this or a former

Act;

(i) wilfully interferes with a headgate, ditch or controlling works which an engineer or

water bailiff has regulated, or destroys a notice posted by an applicant, engineer

or water bailiff;

(j) constructs, maintains, operates or uses works without authority;

(k) puts into a stream any sawdust, timber, tailings, gravel, refuse, carcass or other

thing or substance after having been ordered by the engineer or water recorder

not to do so;

(l) diverts water from a stream without authority.

Right to use unrecorded water

42.(1) It is not an offence for a person to divert water from a stream for extinguishing a fire, but

any flow so diverted shall be promptly restored to its original channel when the fire is

extinguished.

42.(2) It is not an offence for a person to divert unrecorded water for domestic purpose or for

prospecting for mineral, but in a prosecution under this Act the person diverting the water

must prove that the water is unrecorded.


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APPENDIX IISALMONID HABITAT

Salmonid ResourceB.C. and Yukon freshwater systems support 11 salmonid species, including five species of

salmon (chum, coho, chinook, sockeye and pink), three species of trout (rainbow, cutthroat and

brown), and three species of char (Dolly Varden, lake trout and brook trout). The trout, char and

several other resident freshwater species, including Arctic grayling, kokanee, burbot and several

whitefish species, share habitats and have similar environmental requirements as salmon.

Although this reference focuses on salmonids and their habitat, much of its content applies to all

species that share the same freshwater systems.

Salmonid Life HistoriesAnadromous salmonids utilize the ocean for a major portion of their growth, but depend on

freshwater for reproduction. Perhaps the most significant characteristic of anadromous

salmonids is their habit of returning from the ocean to spawn in their natal streams, where they

were spawned and reared. This homing characteristic enables the development of distinct and

separate stocks or populations, each adapted to the particular conditions of its natal stream. One

of the more obvious manifestations is the difference between populations in the seasonal timing

of adult migration and spawning in freshwater. Each of the salmonid species is unique with

respect to its life cycle and habitat requirements in the freshwater phase. All species of

anadromous salmonids require a freshwater environment for spawning and embryonic

development, but the species differ in the extent to which they rear in freshwater after emerging

from the gravel as fry. Pink and chum salmon, for example, migrate to sea immediately following

emergence, whereas the other species may rear in streams, lakes or estuaries for periods of

months to several years before entering saltwater. The generalized life cycle of the anadromous

salmonid is shown in Figure A2.1.

There are significant differences in the life histories of the Pacific salmon, trout and char. While

Pacific salmon die after spawning, trout and char may survive to spawn more than once. Salmon

and char characteristically spawn in the fall, on declining temperatures, but trout spawn in winter

or spring, generally on a rising temperature regime. All species use the gravel bottom of streams

or upwelling groundwater sources for spawning. The spawning nest or redd, which is constructed

by the female, consists of a series of pockets in the gravel in which the fertilized eggs are

deposited to a depth of 20 to 50 cm. Development of the embryo goes through the egg stage to

hatching, then through alevin development to full absorption of the yolk sac and subsequent

emergence of fry from the gravel. The period from spawning to fry emergence may range from


117

as little as 2 months in the case of spring-spawning trout, to as much as 9 months for those

Pacific salmon populations spawning in colder periods, where temperatures close to 0°C prevail

through most of the winter. In the latter case, spawning would likely occur in early to mid

September, eggs would reach the eyed stage (when the eyes, head and body form of the embryo

first become apparent) during October, hatching would occur in the following March and April,

and the fry would emerge during May. With the exception of the coastal cutthroat trout and

anadromous Dolly Varden char which utilize nearshore intertidal and estuarine areas, many races

of anadromous salmonid species undertake extensive feeding migrations in the Pacific Ocean,

between northern California and the Gulf of Alaska, and can be found up to 1600 km offshore.

Conversely, other races of salmonid species remain and feed in coastal waters, such as Georgia

Strait, throughout their marine life. In addition, several species of trout and char have exclusively

freshwater life histories with adult migration, spawning, incubation and rearing occurring in and

between lakes, rivers and streams.


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Figure A2.1 Anadromous Salmonid Life Cycle

Salmonid Habitat RequirementsSalmonids are a group of fishes adapted to the variable habitat of north temperate, "recently"

deglaciated regions. Individually, they often have to cope with severe and variable conditions

and might be thought of as an especially "tough" or "insensitive" group of species. Certainly they

appear to be remarkably resilient in habitat use, in feeding, growth and reproduction, as well as in

many other ecological and behavioural characteristics. Despite this, they are environmentally

sensitive fishes; particularly in terms of the habitat and water quality requirements of the

incubating and rearing portions of their life cycle. The typical food items for those species that

utilize streams for nursery purposes are terrestrial and aquatic invertebrate animals whose own

life cycles depend on similar habitat and water quality values as salmonids.

In general, salmonids require fairly cool, well-oxygenated water, a clean gravel substrate, and

abundant cover and shade. They require special conditions for successful spawning, for the


119

development and hatching of eggs and for growth and survival of their young. Salmonids have

different requirements for spawning, rearing and migration. Fry and juveniles move to different

habitats as they grow older, and hence they require access up and down the stream and into

smaller tributaries. This may include swampy areas, wetlands, small streams and side channels

or intermittently wetted areas. As spawning adults, salmonids require adequate flow and access

to return to spawning areas to complete their life cycle.

The range and diversity of aquatic environments the various salmonids inhabit throughout their

life history combine to make them much more vulnerable to environmental changes. These

changes are generally associated with water use and impacts of land use activities on the aquatic

environment. Water diversions and pollution, hydroelectric projects, forest harvesting, road

construction and land development are the most predominant. The use by salmonids of habitat

varies widely not only with species but also with races of a species, between discrete populations

and even between individuals of the same population. This makes any generalization about their

areas of preference and habitat requirements difficult. Furthermore it means that ideally their

protection and management must be based on specific and up-to-date information about local

populations and conditions.

Specific environmental requirements of salmonids vary with species; in fact, the requirements of

certain species may be in direct conflict (e.g. a small log jam may create a nursery area for coho

salmon but remove a spawning area from chum or pink salmon). However, an attempt has been

made below to generalize the optimum requirements under the simple headings of the habitat

characteristics and water conditions of the salmonid freshwater environment.

Access

The spawning and nursery areas of streams must be accessible to adult salmonids migrating

upstream, and to fry and juveniles seeking rearing habitat. This includes small feeder streams,

wetlands and side channels which provide valuable habitat in the stream or river environment.

Stream Flow

A relatively stable flow without extreme freshets and droughts characterizes the best salmon and

trout streams. Stable stream flow is characterized by a minimum of freshets and floods causing

excessive bed load transport and bank instability, consequently destroying benthos or any

developing embryos or alevins that might be in the substrate. While too much water might be

detrimental, too little is also damaging. A sufficient flow of water is required for each life stage.

Sufficient flows are required during the normal low flow period of late August and September to

provide adequate nursery area for the young salmonids and access for returning spawners, and

also during the winter, when embryos and alevins in the gravel could be exposed to freezing.


120

Stream Substrate

For successful spawning, salmonids require clean stable gravel, typically located in riffles or runs,

depending on fish size and species. High quality gravel will permit redd building and an

intragravel flow of water adequate to provide each embryo and alevin with a high concentration of

dissolved oxygen and to remove metabolic wastes such as carbon dioxide and ammonia. Clean

spawning gravel, from 5 mm to 150 mm in diameter, and larger rocks and cobbles, found on the

stream bottom and banks, is required for production of aquatic insects and habitat for young

juvenile salmonids.

Riparian Cover and Stream Structure

Stream salmonids require cover in the form of undercut banks, logs, rubble substrate, turbulence,

deep pools and overhanging streamside vegetation as found in a viable healthy riparian area.

Such cover is used by juveniles for feeding areas, as a source of food items, refuge for escape

and over-wintering. Adult salmonids use cover such as deep pools for resting and escape during

spawning migrations. Research has also shown that in order to have substantial mixed

populations of salmonids such as the commonly found associations of steelhead trout and coho

salmon or cutthroat trout and coho, a stream with a stepped gradient and high proportion of both

riffles and pools is required. LOD (large organic debris) or CWD (coarse woody debris) form an

integral part of the stream morphology by stabilizing the stream bed and by providing habitat, by

altering the stream structure with scours and pools. Naturally occurring LOD, in the form of fallen

logs, root wads and small jams, should not be altered or removed.


121

Water Temperature

A temperature between 12 and 14°C is preferred by the young of all salmon species with marked

avoidance of temperatures above 15°C and lethal temperature of about 24-25°C. Increased

stream temperature means more dissolved oxygen is needed for the increased metabolic rate of

fish. However, dissolved oxygen saturation levels decrease with increasing temperature which

leads to overall lower concentrations of dissolved oxygen available at higher temperatures.

Dissolved Oxygen (DO)

Stream-dwelling salmonids require high levels of dissolved oxygen (DO) in both the intragravel

and surface waters. It is difficult to set down useful minimum oxygen requirements for stream

salmonids given the great diversity of requirements for different lifestages, activities and stresses

any population experiences. However, it must be stressed that temperature and water quality

markedly affect the levels of DO saturation (% of total saturation at a given temperature) and

concentration (mg/l) in stream waters. Generally, optimum DO saturation is > 90% and minimum

optimum DO concentration is > 8 mg/l.

Water Clarity and Suspended Sediment

Stream water must be clear enough to permit the sunlight to reach the stream bottom and the

algal community where most of the primary production of a stream occurs. Elimination of such

production may severely reduce the invertebrate fauna of a stream. Salmonids feed by sight and

can have difficulty finding food items in highly turbid water. High concentrations of suspended

solids may also directly damage invertebrates and fish, primarily their fragile gill structures.

Additional impacts can occur if suspended sediments settle onto stream bottoms and suffocate

salmonid eggs and alevins, and destroy benthic invertebrate populations.


122


123

APPENDIX IIIOPERATING WINDOWS FOR FISHERIES SENSITIVE ZONES

PurposeThe purpose of this Appendix is to provide development proponents with general information on

the allowable operating windows within Fisheries Sensitive Zones based on FSZ area and fish

species present. To assist in the presentation of this information, the Appendix has been divided

into two sections.

Fisheries Sensitive Zone Areas of British ColumbiaFigure A3.1 is a map of British Columbia dividing the province into nine (9) FSZ areas to illustrate

the regional variations in fish presence and use of Fisheries Sensitive Zones (FSZ). The

rationale underlying this division was initially ecological, as per Demarchi's Ecoregions of British

Columbia (1988)1. However, it was found to be necessary to adjust the ecological basis to

reflect major drainage basins and fish species distribution2, and to reflect some major

administrative regions3. To aid in habitat protection, Fisheries Sensitive Zones (FSZ) were

defined as the out-of-stream features of fish habitat, such as side channels, wetlands and riparian

areas, in addition to instream fish habitat features.

Fisheries Sensitive Zone Species Timing WindowsTable A3.1, titled Fisheries Sensitive Zone Species Timing Windows , gives time periods of

reduced risk for important commercial, sport, and resident fish species within each of the nine

FSZ areas shown on the FSZ Area map. Within each FSZ Area, there are defined operating

windows for fish species within that region based on the biological life histories within each of the

areas. The period noted in the table is considered to be that time span when there are no fish

eggs or alevins present in the substrates of the rivers in the designated area for the species of

fish indicated (i.e. the start date of the window coincides with the end of alevin emergence and

the end date of the window coincides with the start of spawning by the species in question).

1 Shown by the inclusion of the headwaters of the Klinaklini and Dean Rivers within Area 4 rather than Area 1.2 Shown by the exclusion of the upper Fraser River from Area 3, which now generally covers the Columbia River basin,

and by the division of the northern portion of the province into the Peace River basin, the Liard River basin and theAlaska Panhandle transboundary rivers area.

3 Shown by the division of the mainland coast into a southern portion, included with Vancouver Island in Area 1, and anorthern portion, included with the Skeena and Nass drainage basins in Area 5.


124

The use of the Operating Windows for Fisheries Sensitive Zone Areas is governed by the

following principles:

•• The individual life history windows noted in the table are general approximations only for

a particular species over an entire specified area. Given the great extent of many of the

nine areas, variations from the noted windows should be expected. Depending on the

area, the location of a particular river system within that area, the species of concern,

and expected conditions (e.g. stream temperature, fry emergence and migration, etc.)

during the proposed work period, the actual permissible window for work in the FSZ

will likely be defined and negotiated with input from both federal and provincial fisheries

agencies, with decisions being based on the physical and biological parameters of the

ecosystem. For instance, in some cases, it may be necessary to consider hydraulic

conditions in conjunction with the biological life histories. Times when sensitive life

history stages (including organisms other than fish) are absent may also be times of low

flow. Any suspended solids generated by work in the FSZ at these times may not be

flushed out of the system quickly and the subsequent degradation of fish habitat and

water quality could impact future migrating, spawning, and rearing populations as well as

their food sources. Potential impacts on existing populations may have to be balanced

with those on future populations. In any case, the goal will be the protection of fish and

fish habitat through stringent safeguards to prevent the introduction of deleterious

substances, including sediment, into the FSZ.

•• The reduced-risk windows noted in the table are those periods when fish eggs and

alevins are absent from the substrates. Juvenile fish and/or migrating/resident adults will

probably still be present in the river during the period of reduced risk. Although a work

period for a particular FSZ may be identified and approved, the actual work still must be

carried out in a manner that, as clearly stated above, avoids the degradation of fish

habitat. The reduced-risk windows noted in the matrix do not give "carte blanche"

permission for poor or careless work practices; the objective is to always avoid adverse

impacts on fish and fish habitat. Reduced-risk is not no-risk.

•• The presentation of those fish species listed in the timing window matrix is not intended

to imply that other fish species will be excluded from consideration when actual

permissible windows are being negotiated. It is quite possible that the protection of rare

or endangered species, or of specific populations of such species, and of their habitats

will assume greater importance than that of the listed species.

The windows in the table are provided as an aid for initial planning only. Given the

likelihood that actual permissible windows will have to be determined by both federal

and provincial officials, development proponents are strongly encouraged to contact


125

local DFO and MOELP fisheries regional staff early in the planning process to discuss

site-specific details of any work in Fisheries Sensitive Zones.

Figure A3.1 Fisheries Sensitive Zone Areas of British Columbia


126

Table A3.1 - Fisheries Sensitive Zone Species Timing Windows


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REFERENCES

Dane, B.G. 1978. Culvert Guidelines: Recommendations for the Design and Installation of

Culverts in British Columbia to avoid conflict with Anadromous Fish. Tech. Rep. No.

811. Fisheries and Marine Service. Fisheries and Environment Canada.

Design of Urban Runoff Quality Controls: Proceedings of an Engineering Foundation

Conference on Current Practice and Design Criteria for Urban Quality Control. 1989.

ASCE. New York.

Elbe, H. and R. Olmsted. Guidelines for the Protection of the Aquatic Environment during Land

Development Activities. 1990. Prepared for Department of Fisheries and Oceans and

Ministry of Environment.

Erosion and Sediment Control - Westwood Plateau Coquitlam, BC. Prepared for Westbild

Enterprises Ltd by Terrasol and Hardy BBT Geotechnical Engineers Ltd. 1990.

Facts Sheets prepared for B.C. Ministry of Transportation and Highways - Seminar on

Highway Maintenance. May 1990. Prepared by Department of Fisheries and Oceans.

1989.

Fish Screening Directive. 1990. Department of Fisheries and Oceans Canada.

Gibb, A., B. Bennett and A. Birkbeck. 1991. Urban Runoff Quality and Treatment: A

Comprehensive Review. BC Research. Vancouver.

Goldman, S.J., K. Jackson and T.A. Bursztynsky. 1986. Erosion and Sediment Control

Handbook. McGraw-Hill Book Company. New York.

Gray, D.H. 1982. Biotechnical Slope Protection and Erosion Control. Van Nostrand Reinhold

Co. New York.

Hogg, W.D. and D.A. Carr. 1985. Rainfall Frequency Atlas for Canada. Atmospheric

Environment Service. Environment Canada.

Katopodis, C. and R. Gervais. 1991. Ichthyomechanics. Freshwater Institute. Central and Arctic

Region. Department of Fisheries and Oceans Canada.

Loukidelis, D and A. Hillyer. Using Conservation Covenants to Preserve Private Land in British

Columbia. 1992. West Coast Environmental Law Research Foundation. Vancouver.

McKinley, W.R. and R.D. Webb. 1956. A Proposed Correction of Migratory Fish Problems at

Box Culverts. Department of Fisheries. State of Washington.


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Munday, D.R., G.L. Ennis, D.G. Wright, D.C. Jefferies, E.R. McGreer, and J.S. Mathers, 1986.

Development and Evaluation of a Model to Predict Effects of Buried Underwater

Blasting Charges on Fish Populations in Shallow Water Areas. Can. Tech. Rep.

Fisheries and Aquatic Sciences No. 1418.

Nonpoint Source Watershed Workshop. 1991. U.S. Environmental Protection Agency.

Policy for the Managment of Fish Habitat. 1986a. Department of Fisheries and Oceans Canada.

Powers, P.D. 1990. Stormwater Detention Performance based on Dominant Discharge.

Department of Fisheries. State of Washington.

Powers, P.D. 1991. Stormwater Management Guidelines for the Protection of Fish Habitat.

Department of Fisheries. State of Washington.

Stormwater Management Manual for the Puget Sound Basin. Draft 1991. Department of

Ecology. State of Washington.

Urban Development: Guidelines for the Protection of Fish Habitat in Insular Newfoundland.

1983. Department of Fisheries and Oceans.

Urban Hydrology for Small Watersheds Technical Release 55. 1986. Soil Conservation

Service. U.S. Dept. of Agriculture.

Urban Runoff Quality Control Guidelines for the Province of British Columbia. Draft 1992.

Municipal Liquid and Industrial Waste Managment Branch. Province of British Columbia.

Urban Storm Drainage Criteria Manual - Volume 3 - Best Management Practices. Urban

Drainage and Flood Control District. Denver, Colorado. 1992.

Vancouver Island Highway Project - Guidelines for Environmental Design of Highway

Drainage. Prepared for the B.C. Ministry of Transportation and Highways by KPA

Engineering Ltd. 1992.

Westwood Plateau Development Plan. 1990. Westbild Enterprises Ltd.


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